Communication device and communication system

ABSTRACT

Estimates a position of a communication device  200  after a specific time according to a position detecting unit  207  that detects its own position, a communication status storage unit  202  that stores communication status data  202   a  indicating a wireless communication status at each position, and the position detected by the position detecting unit  207 , and includes a prediction unit  204  that predicts the wireless communication status at the position with reference to the communication status data  202   a  and a prediction processing unit  205  that executes a handling process for disconnection of the communication due to deterioration of the wireless communication status based on a prediction result by the prediction unit  204.

BACKGROUND OF THE INVENTION

[0001] (1) Field of the Invention

[0002] The present invention relates to a communication device and a communication system that performs communication via a wireless communication medium, especially relates to a mobile communication device installed to a mobile object like an automobile or carried with a user, and to a communication system equipped with the communication device.

[0003] (2) Description of the Related Art

[0004] In recent years, an automobile telephone and a portable telephone that perform communication via a wireless communication medium, and a communication device like a hands-free device that enables a user to perform communication without holding the device in his hand, have been popular.

[0005] This type of the communication device is movable with an automobile if it is installed to the automobile, or with a user if it is carried by the user. Because of this, if the automobile or the user moves to an area where a radio wave as a wireless communication medium does not easily reach, i.e. the area in a poor communication status, it becomes impossible to do the communication with a device such as other telephone and a telephone call may suddenly be disconnected. For example, since the communication status is not good in a tunnel or in a mountain area, any communication becomes impossible for the communication device installed to the automobile when the automobile drives through such areas.

[0006] Therefore, when approaching an area in the poor communication status, a communication device, which informs the fact, has already been proposed as a conventional invention. (For example, see the Japanese Laid-Open Patent Application No. 4-286430 (Patent Document 1).)

[0007]FIG. 1 shows a structure diagram of a communication device (an automobile telephone) in the above Patent Document 1.

[0008] As shown in the FIG. 1, the communication device in the Patent Document 1 is a device installed in the automobile, which includes following elements: a geomagnetic sensor 901 that detects a driving direction of the automobile; a speed sensor 902 that detects a driving speed of the automobile; a map data memory unit 903 that memorizes a map; a distribution data memory unit 904 that memorizes a distribution map of a radio wave electric field intensity; a location unit 905 that detects a current location of the automobile, etc.; a telephone 906; a display unit 907 that displays characters and graphics; a speaker 908; an alarm lamp 909; a main controller 910 that controls the telephone 906, the display unit 907 and the like.

[0009] In such communication device, the location unit 905 specifies the current position of the automobile on the map memorized in the map data memory unit 903 according to a detected result of a geomagnetic sensor 901 and the speed sensor 902, and predicts time and a distance possible to perform communication through the telephone 906 with reference to the distribution map of the radio wave electric field intensity memorized in the distribution data memory unit 904. Then, the main controller 910 controls the display unit 907, the speaker 908 and the alarm lamp 909 based on the predicted result, and pre-informs the user that the automobile approaches an area in the bad communication status and a phone call is going to be disconnected.

[0010] Also, similar to the communication device in the Patent Document 1, a communication device installed in the automobile has been provided, which pre-alarms to the user that the automobile approaches an area in the bad communication status and a telephone call is going to be disconnected, specifies the current location of the automobile through GPS functions, and notifies time and a distance possible for communication to the user and his calling party (for example, see the Japanese Laid-Open Patent Application No.10-93497 (Patent Document 2).)

[0011] Additionally, there is a proposed communication device which suspends the user's outgoing call operation to prevent sudden disconnection of a telephone call when the user approaches the area in the bad communication status (for example, see the Japanese Laid-Open Patent Application No. 10-313484 (Patent Document 3).)

[0012] The communication device (a hands-free device) of this Patent Document 3 is a device installed to the automobile, which predicts whether or not the automobile reaches the area in the bad communication status after a specific time from the current location, and suspends an outgoing call if the automobile reaches the area. Then, it makes the outgoing call, which had been suspended once as above, when it reaches an area in the good communication status. By doing so, it prevents sudden disconnection of telephone calls.

[0013] Although those communication devices in the Patent Document 1 and the Patent Document 2 pre-inform that the area in the bad communication status is approaching and the telephone call is disconnected, the user needs to operate the telephone by himself to terminate the communication normally, which makes the user feel somewhat troublesome.

[0014] Also, in the communication device in the Patent Document 3, a telephone call may suddenly be disconnected if a call is made and being connected to a telephone line but the communication device subsequently goes into an area in the bad communication status. Then, in the same way as the communication devices in Patent Document 1 and the Patent Document 2, the communication device in the Patent Document 3 requires the user's operation to terminate the communication normally due to the deteriorating communication status, which makes the user feel annoying.

[0015] Furthermore, if one of such devices in the Patent Document 1, Patent Document 2 and Patent Document 3 is installed to the automobile and operated through a driver, i.e. the user, he/she is required to drive the automobile with being annoyed by troublesome operation, which may cause a car accident due to a luck of his/her concentration on the driving.

SUMMARY OF THE INVENTION

[0016] In view of the above problems, the present invention aims at providing a communication device and a communication system that reduce the user's nuisances in a situation moving through an area in a bad communication status such as a tunnel or a mountain area.

[0017] To achieve the above objective, a communication device that is mobile and performs communication via a wireless communication medium comprising: a position detecting unit operable to detect own position; a communication status retaining unit operable to retain communication status data content indicating a wireless communication status at each position; a prediction unit operable to estimate a position of the communication device at the time when a specific time elapses according to the position detected by the position detecting unit, and predict the wireless communication status at the position with reference to the communication status data; and a processing unit operable to execute a handling process for disconnection of the communication due to deterioration of the wireless communication status based on a prediction result by the prediction unit.

[0018] In this way, a status of wireless communication is predicted and a process is executed for a measure against disconnection of the communication according to degradation of the communication status. Therefore, even if the communication device is moved through the area in the bad communication status such as the tunnel or the mountain area, it does not require any operations of the user to cope with a change in the status and can reduces the user's nuisances.

[0019] Additionally, the processing unit may have a feature to terminate communication when the communication is predicted to be disconnected based on a prediction result by the prediction unit.

[0020] In this way, the user's annoyance is reduced because it does not require any operations to terminate the communication even if he/she brings the communication device into, for example, a tunnel.

[0021] Moreover, the processing unit may have features to specify the wireless communication status at the position detected by the position detecting unit with reference to the communication status data, and execute a reconnection process when the disconnected communication is decided to be re-connectable based on the specified wireless communication status.

[0022] By doing so, when the user who's carrying the communication device gets out from the tunnel, the communication is reconnected without requiring the user's connection operation so that it reduces annoyance of the user.

[0023] In order to achieve above objective, the communication system related to the present invention where a mobile communication device communicates with other communication device via a wireless communication medium, comprising: a mobile communication device that performs wireless communication; a position detecting unit that detects a position of the mobile communication device; a communication status storage unit that retains communication status data content indicating a wireless communication status at each position; a prediction unit that estimates a position of the mobile communication device at the time when a specific time elapses based on the position detected by the position detecting unit, and predicts the wireless communication status at the position with reference to the communication status data; and a processing unit that executes a handling process for disconnection of the communication between the mobile communication device and other communication device due to deterioration of the communication status based on a prediction result by the prediction unit.

[0024] In this way, the wireless communication status of the mobile communication device is predicted and a process is executed for a measure against disconnection of the communication between the mobile communication device and other communication device due to the deteriorating status of the wireless communication. Therefore, nuisances of the user of the mobile communication device are lightened because he/she is not required to perform any operation even in a changeable situation the mobile communication device is moved via an area in the poor communication status such as tunnels and mountain areas.

[0025] The processing unit may also include a feature of having the mobile communication device terminate the communication when the communication between the mobile communication device and the communication device is predicted to be impossible based on the prediction result of the prediction unit.

[0026] By doing so, even if the user of the mobile communication device takes the mobile communication device with him/her into a tunnel, etc., the user is not required to terminate the communication so that the user's annoyance is removed.

[0027] Additionally, the communication, system may further includes a relaying unit that relays a signal exchanged between the mobile communication device and the communication device, and the processing unit specifies a wireless communication status at the position detected by the position detecting unit with reference to the communication status data, and maintains the communication between the relaying unit and the communication device and puts the communication device on hold when deciding the communication between the mobile communication device and the relaying unit becomes impossible based on the specified wireless communication status.

[0028] In this way, when the user of the mobile communication device carries the mobile communication device with him/her and goes through somewhere such as a tunnel, the communication device is put on hold. Therefore, the user of the communication device is not required to do any operations for the communication device other than waiting, so that the annoyance that the user of the communication device may feel can be lightened.

[0029] The present invention may also be embodied as a communication method used for a mobile communication device to communicate via a wireless communication medium, as a communication method used for a communication system to make a mobile communication device communicate with other communication device via a wireless communication medium, and as a program to have a computer execute steps included in these method.

Further Information about Technical Background to this Application

[0030] The following applications are incorporated herein by references:

[0031] Japanese Patent Application No. 2003-013361 filed Jan. 22, 2003;

[0032] Japanese Patent Application No. 2003-013362 filed Jan. 22, 2003;

[0033] Japanese Patent Application No. 2002-269190 filed Sep. 13, 2002.

BRIEF DESCRIPTION OF DRAWINGS

[0034] These and the other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings which illustrate a specific embodiment of the invention. In the drawings:

[0035]FIG. 1 is a diagram to show a structure of a conventional communication device.

[0036]FIG. 2 is an external view of a communication device for the first embodiment according to the present invention.

[0037]FIG. 3 is a block diagram to show a structure of the above communication device.

[0038]FIG. 4 is a data content diagram to show content of the above communication status data.

[0039]FIG. 5 is an explanatory diagram to describe a method for the above prediction unit to estimate its own position after a specific time.

[0040]FIG. 6 is an explanatory diagram to describe a method for the prediction unit to estimate its own position after a specific time period according to the above searched route.

[0041]FIG. 7 is an action flow diagram to show a series of actions taken by the above time reporting unit.

[0042]FIG. 8 is an action flow diagram to show a series of actions taken by the above connecting unit.

[0043]FIG. 9 is an explanatory diagram to describe how the above automobile drives through two tunnels.

[0044]FIG. 10 is an action flow diagram to show a sample action taken by the above call regulation unit.

[0045]FIG. 11 is a diagram to show a sample screen displayed in the above display unit.

[0046]FIG. 12 is an action flow diagram to show characteristic actions taken by the above communication device.

[0047]FIG. 13 is a diagram to show a structure of a communication system for the second embodiment according to the present invention.

[0048]FIG. 14 is a block diagram to show an internal structure of a server and a portable telephone of the above communication system.

[0049]FIG. 15 is a data content diagram to show content of the above communication status data.

[0050]FIG. 16 is a data content diagram to show content of the above prediction data.

[0051]FIG. 17 is an action flow diagram to show a series of actions taken by the above time reporting unit.

[0052]FIG. 18 is an action flow diagram to show a series of actions taken by the above connecting unit.

[0053]FIG. 19 is an explanatory diagram to describe how the automobile in which the above portable telephone is brought drives through two tunnels.

[0054]FIG. 20 is an action flow diagram to show a sample action taken by the above call regulation unit.

[0055]FIG. 21 is a screen diagram to show a sample screen displayed in the above display unit.

[0056]FIG. 22 is a sequence diagram to show characteristic actions taken by the above communication system.

[0057]FIG. 23 is a diagram to show a structure of a communication system related to the above variation sample.

[0058]FIG. 24 is an explanatory diagram to describe a prediction method for the time reporting unit to predict calling time and reconnection time in the above variation sample.

DESCRIPTION OF PREFERRED EMBODIMENT(S)

[0059] The following specifically describes the present invention based on several embodiments with reference to drawings.

[0060] (First Embodiment)

[0061] The following describes a communication device related to a first embodiment of the present invention.

[0062]FIG. 2 is an external view of a communication device for the first embodiment according to the present invention.

[0063] This communication device 200 is a device for reducing a user's nuisances in a situation the user moves via an area in a poor communication status such as tunnels and mountains, which is installed to an automobile and structured as a hands-free device containing a car navigation system function. That is to say, this communication device 200 obtains Global Positioning System (GPS) data indicating a position and the like from a GPS satellite, navigates the user who drives the automobile to his destination, and additionally enables the user to communicate through a portable telephone 221 without having him hold the portable telephone 221 in his hand (hands-free communication).

[0064] This type of communication device 200 comprises a main body 200 a embodied in a front panel, a console box or the like within the automobile, a microphone 220 which collects the driver's voices and installed at a rearview mirror or somewhere, four speakers 231˜234 located to transmit sounds widely in the automobile, and a portable telephone 221 which is brought into the automobile and communicates with the main body 200 a.

[0065]FIG. 3 is a block diagram to show a structure of the communication device 200 in this embodiment.

[0066] The main body 200 a of the communication device includes following elements: a position detecting unit 207 that obtains the above GPS data from the GPS satellite and detects its own position based on the GPS data; a map memory unit 201 that pre-memorizes map data 201 a indicating a map; an operation unit 212 that contains operating buttons or the like to enter, for instance an automobile's goal (destination) and outputs an operation signal according to operations through the operating buttons; a navigation unit 203 that generates navigation data including information necessary to navigate the user from the position detected by the position detecting unit 207 to the destination; a display unit 206 that displays a graphic, a character or the like such as a map of a surrounding area; a road information obtaining unit 210 that obtains road traffic information such as through Vehicle Information and Communication System (VICS); and a control unit 213 that controls the above position detecting unit 207 and navigation unit 203 according to the operation signal from the operation unit 212, makes the display unit 206 display a map containing the current position and its surrounding and a route to the destination or the like, and makes the speakers 231˜234 output a guiding voice or the like. While the map memory unit 201 may be embodied as ROM (Read Only Memory), RAM (Random Access. Memory) or the like, the control unit 213 is structured as CPU (Central Processing Unit) or the like.

[0067] The position detecting unit, 207 obtains the GPS data, detects its own position such as “135° 25′ 30 east longitude, 40° 30′25″ north latitude”, generates detected position information indicating the detected position, and outputs it to the control unit 213.

[0068] The road information obtaining unit 210 obtains the road traffic information distributed from a VICS center via a beacon, etc. located on a road. This road traffic information contains content that informs traffic conditions of the road the automobile is currently driving and of its surrounding roads.

[0069] The navigation unit 203 obtains the detected position information generated by the position detecting unit 207 according to an instruction from the control unit 213, recognizes the destination entered from the operation unit 212 via the control unit 213, and reads out the map data 201 a from the map memory unit 201 which contains the area from the position indicated in the detected position information to the destination. Then, the navigation unit 203 searches a route from the position indicated in the detected position information to the destination. At this point, the navigation unit 203 obtains road traffic information from the road information obtaining unit 210 via the control unit 213 and searches the route to reach the destination in a quickest way or in a shortest distance along with consideration of traffic conditions, etc. indicated in the road traffic information. Then, the navigation unit 203 outputs the searched route and navigation data indicating the current position of the automobile on the map to the control unit 213.

[0070] The control unit 213 makes the display unit 206 display the map containing the current position of the automobile and its neighborhood with the searched route according to the navigation data obtained from the navigation unit 203, and makes the speakers 231˜234 output the guiding voice, for example “Please turn left at a next crossing”.

[0071] In this way, the communication device 200 operates as a terminal of a car navigation system because it includes aforementioned navigation unit 203 or the like, and navigates the user as a driver to his destination. Also, because this main body 200 a contains the road information obtaining unit 210, it can search the most appropriate route along with consideration of traffic conditions.

[0072] In addition, the main body 200 a of this communication device 200 includes a portable telephone specific communicating unit 211. When a telephone line is connected between the portable telephone 221 and other telephone, the portable telephone specific communicating unit 211 obtains, through the communication with the portable telephone 221, a sound signal indicating a voice of the driver from the microphone 220, sends the sound signal to the telephone via the portable telephone 221, and obtains, via the portable telephone 221, a sound signal indicating a voice of the calling party sent from the telephone.

[0073] This portable telephone specific communicating unit 211 communicates with the portable telephone 221 according to a communication standard of, for example, Bluetooth (a trademark of the Bluetooth SIG Incorporated).

[0074] When the control unit 213 obtains the operation signal that instructs to make a call to the telephone with a specific telephone number from the operation unit 212, it makes the portable telephone specific communicating unit 211 communicate with the portable telephone 221 to make the call from the portable telephone 221 to the telephone. When the telephone line is connected between the portable telephone 221 and the telephone, the control unit 213 makes the driver's voice collected through the microphone 220 be output from the telephone, and makes the calling party's voice be output from the speakers 231˜234 based on the calling party's sound signal from the telephone.

[0075] According to this, when the driver brings his portable telephone 221 into the automobile, he can make telephone calls with the portable telephone 221 without holding it in his hand.

[0076] Moreover, the main body 200 a in this embodiment contains following elements: a direction detecting unit 208 that specifies a driving direction of the automobile by detecting directions of geomagnetic fields (east/west/south/north) and outputs direction information indicating its driving direction; a speed detecting unit 209 that detects a wheel rotation speed of the automobile and outputs speed information indicating a driving speed of the automobile; a communication status storage unit 202 that stores communication status data 202 a indicating a communication status at each position on the map; a prediction unit 204 that estimates its own position after a specific time based on the detected position information, direction information and speed information and predicts the communication status at the estimated position with reference to the communication status data 202 a; and a prediction processing unit 205 that executes each process such as a communication connecting process based on the predicted results by the prediction unit 204. The speed detecting unit 209 may also detect the driving speed of the automobile by detecting an automobile speed pulse. The prediction processing unit 205 is equipped with a time reporting unit 205 a, a connecting unit 205 b and a call regulation unit 205 c, which are described later. Here, the communication status storage unit 202 is constructed as ROM (Read Only Memory) or RAM (Random Access Memory) and the like, while the prediction unit 204 and prediction processing unit 205 are structured as CPU (Central Processing Unit), etc.

[0077]FIG. 4 is a data content diagram to show content of the communication status data 202 a.

[0078] As shown in this FIG. 4, the communication status data 202 a has a position information field A1 and a communication level field A2. Position information to show each position, for example “longitude X1, latitude Y1” or “longitude X2, latitude Y2”, is registered in the position information field A1, and a communication level at each position indicated in the position information is registered in the communication level field A2. This communication level describes the communication status with, for example 10 levels, starting from the communication level “1” as the worst communication status to “10” as the best communication status. For instance, in the communication status data 202 a shown in FIG. 3, the position of “longitude X1, latitude Y1” is registered to be the worst communication status, while the position of “longitude X3, latitude Y3” to be the best communication status.

[0079]FIG. 5 shows an explanatory diagram that describes a method for the prediction unit 204 to estimate its own position after a specific time.

[0080] For example, if the automobile catering this communication device 200 is currently at a position P0 and driving to a south-east direction indicated with a solid arrow line in FIG. 5 at approx. 40 [km/hr], the position detecting unit 207 detects that the automobile is at the position P0 and outputs the detected position information indicating the detected result. Also, at this point, the direction detecting unit 208 detects that the automobile is facing towards the south-east direction and outputs the direction information indicating the detected result. The speed detecting unit 209 detects the driving speed of the automobile is at approx. 40 [km/hr] and outputs the speed information indicating the detected result.

[0081] Once the prediction unit 204 obtains the above detected position information, direction information and speed information, it estimates that the automobile after a minute is going to be at position P1 for a driving distance of 40×1/60 [km] from the position P0 to the south-east direction.

[0082] Then, the prediction unit 204 searches the position information indicating the position P1 from the communication status data 202 a memorized in the communication status storage unit 202 and reads out the communication level at the position P1. For example, if the position P1 is “longitude X2, latitude Y2”, the prediction unit 204 reads out the communication level “9” corresponded to the position information indicating “longitude X2, latitude Y2” from the communication status data 202 a, and predicts the communication level after a minutes will be “9”.

[0083] In this way, the prediction unit 204 predicts the communication level after a specific time. For example, it predicts the communication level after a minute, 2 minutes, 3 minutes . . . and so on.

[0084] Also, when the route to the destination is searched by the navigation unit 203 and the control unit 213 is navigating to the destination with the display unit 206 and speakers 231˜234 based on the navigation data, the prediction unit 204 estimates the position of the automobile after a specific time based on the searched route.

[0085]FIG. 6 is an explanatory diagram that describes a method for the prediction unit 204 to estimate its own position after a specific time based on the searched route.

[0086] The prediction unit 204 recognizes the position of the automobile on the searched route from the detected position information, and estimates the position of the automobile after a specific time along with the searched route based on the speed information. For example, as shown in FIG. 6, the prediction unit 204 estimates, according to the driving speed at the current position P00 on the searched route, the automobile will be located at position P01 after a minute, at position P02 after 2 minutes and at position P03 on the after 3 minutes on the searched route.

[0087] Here, when estimating the position of the automobile after a specific time, the prediction unit 204 takes account of the road traffic information obtained by the road traffic information obtaining unit 210. Namely, when the obtained road traffic information indicates the traffic ahead of the automobile on the searched route is busier than the current position, the prediction unit 204 estimates the position of the automobile after a specific time, assuming that the automobile will drive slower (for example, at 20 km/hr) than the current speed (for example, at 40 km/hr) in the busy area. Also, if the obtained road traffic information shows the road ahead on the searched route has less traffic than the current position, the prediction unit 204 estimates the position of the automobile after a specific time, assuming the automobile will drive faster (for example, 60 km/hr) than the current speed (for example, 40 km/hr) in that area. By using the road traffic information in this way, the prediction unit 204 can estimate the position of the automobile more accurately and predict the communication level more precisely.

[0088] Moreover, the map data 201 a memorized in the map memory unit 201 contains information related to a speed limit for each road (speed limit information). Then, the prediction unit 204 takes account of the speed limit information contained in the map data 201 a when estimating the position of the automobile after a specific time. That is to say, in the above example, even though the automobile currently driving at 40 km/hr is presumed to drive at 60 km/hr on the road ahead according to the road traffic information, the prediction unit 204 estimates the position of the automobile after the specific time along with consideration of the speed limit information. Therefore, if the speed limit on the road ahead indicates 50 km/hr in the speed limit information, the prediction unit 204 actually assumes its driving speed will be 50 km/hr and estimates the position of the automobile after the specific time. By using the speed limit information in this way, the prediction unit 204 can estimate the position of the automobile more accurately and predicts more precise communication level.

[0089] The prediction unit 204 predicts above type of the communication level per specific time duration or by each specific distance based on the latest detection result output from the position detecting unit 207, the direction detecting unit 208 and the speed-detecting unit 209. It is also possible that the prediction unit 204 handles its prediction according to changes in the communication status. When there are radical fluctuations in the communication status, the prediction unit 204 may be made to predict the communication level frequently.

[0090] Although the prediction unit 204 in the above case predicts the future communication level in every minute like “after one minute”, “after two minutes”, “after three minutes”, and so on, its time interval is not limited to every minute, and it may be different like “every 10 second”. The time interval, as mentioned above, may be longer or shorter according to changes in the communication status.

[0091] The prediction processing unit 205 includes the time reporting unit 205 a that reports the user and his calling party about the time allowed for communication based on the communication level predicted by the prediction unit 204, a connection unit 205 b that instructs the control unit 213 to conduct a connection process via the telephone line between the portable telephone 221 and other telephone for the automobile going through the area in the poor communication status, a call regulation unit 205 c that regulates incoming and outgoing calls of the portable telephone 221 when the automobile goes through the area in the good communication status just for a short period within the area in the poor communication status.

[0092] In a situation a telephone line is connected between the portable telephone 221 and other telephone and the driver is talking through the hands-free function, if the line is judged to be disconnected because the automobile will reach the area in the bad communication status after a specific time, the time reporting unit 205 a informs the user and his calling party on the calling time (the time allowed for call) allowed until the automobile reaches that area. For example, if the prediction unit 204 predicts the communication level will be “9” after a minute, “8” after 2 minutes, “5” after 3 minutes and “1” after 4 minutes, the time reporting unit 205 a decides the automobile will reach the area in the poor communication status after 4 minutes and ;the line will be disconnected according to the prediction result of the communication level. Then, through the control unit 213, it makes the display unit 206 display characters such as “The line will be disconnected after 4 minutes”, and speakers 231˜234 output an announcement such as “The line will be disconnected after 4 minutes due to the deteriorating communication status” by superimposing it on the voice of the calling party on the phone. Furthermore, the time reporting unit 205 a sends the reporting signal indicating the above announcement or the like to the portable telephone specific communicating unit 211, and makes the portable telephone specific communicating unit 211 send the reporting signal to the telephone of the calling party from the portable telephone 221. As a result of it, the above announcement which is superimposed on the driver's voice is output from the telephone of the calling party.

[0093] In this way, the communication device 200 of this embodiment can avoid sudden disconnection of the line so that the driver who makes a hands-free call and his calling party can recognize in advance when the line is disconnected.

[0094] Additionally, in a situation a telephone line is connected between the portable telephone 221 and other telephone and the driver is talking through the hands-free function, when the line is decided to be disconnected because the automobile will reach the area in the poor communication status after a specific time, and subsequently to be connected after the automobile gets out from the area according to the prediction result by the prediction unit 204, the time reporting unit 205 a informs the user and his calling party about the time allowed for their communication as well as the time required to be re-connectable (time required for reconnection).

[0095] For example, as stated above, suppose the communication level is predicted to be “5” after 3 minutes, “1” after 4 minutes and “2” after 10 minutes. Based on such prediction result, the time reporting unit 205 a decides that the line will be disconnected after 4 minutes when the automobile reaches the area in the poor communication status, and that the line can be reconnected after 10 minutes when the automobile gets out from the area in the bad communication status. Then, the time reporting unit 205 a reports the time allowed for communication as above, and makes, through the control unit 213, the display unit 206 display characters such as “Reconnection is possible after 10 minutes” and the speakers 231˜234 outputs announcements such as “Reconnection is possible after 10 minutes” by superimposing it on the voice of the calling party on the phone. Moreover, the time reporting unit 205 a sends the reporting signal indicating the announcement as above to the portable telephone specific communicating unit 211 via the control unit 213, and has the portable telephone specific communicating unit 211 send the reporting signal from the portable telephone 221 to the telephone of the calling party. As a result of it, the above announcement, which is superimposed on the voice of the driver, is output from the telephone of the calling party.

[0096] Throughout this way, the communication device 200 in this embodiment enables the driver who is on the hands-free phone and his calling party to know the time required for reconnection so that it reduces annoyance of the user and makes it easier to handle it.

[0097] Here, with reference to FIG. 7, the following describes a series of actions taken by the above time reporting unit 205 a of the prediction processing unit 205.

[0098]FIG. 7 is an action flow diagram to show a series of action taken by the time reporting unit 205 a in a situation where a telephone line is connected between the portable telephone 221 and other telephone.

[0099] At first, the time reporting unit 205 a obtains a prediction result of the communication level from the prediction unit 204 (Step S100). Then, the time reporting unit 205 a predicts whether the line will be disconnected or not according to the prediction result (Step S102). If the time reporting unit 205 a predicts the line will be disconnected after 5 minutes (Y in the Step S102), it reports the user and his calling party on the time allowed for communication (5 minutes) with using the display unit 206 and the speakers 231˜234 (Step S104). If the time reporting unit 205 a predicts the line will not be disconnected within a specific time in the Step S102 (N in Step S102), the time reporting unit 205 a repeats to obtain the latest prediction result from the prediction unit 204 and repeats actions from the Step S100.

[0100] Additionally, when the time reporting unit 205 a predicts the line will be disconnected in the Step S102, it further predicts whether the line can be re-connected or not within a specific time based on the prediction result of the communication level obtained by the prediction unit 204 (Step S106). As its result, if the time reporting unit 205 a predicts the line can be reconnected after 9 minutes (Y in the Step S106), it reports the user and his calling party on the time required for reconnection (9 minutes) with using the display unit 206 and speakers 231˜234 (Step S108). Then, the time reporting unit 205 a terminates the process when it recognizes the actual disconnection of the line (Y in the Step S110). If it is not disconnected (N in the Step S110), it repeats actions from the Step S100 again.

[0101] As a result of it, announcements, such as “The line will be disconnected after 5 minutes due to the poor communication status” and “Reconnection is possible after 9 minutes”, and then a minute later, “The line will be disconnected after 4 minutes due to a poor communication status” and “Reconnection is possible after 8 minutes” and so on, are output repeatedly from the speakers 231˜234 and the telephone of the calling party until the line is disconnected.

[0102] Moreover, when reconnection is predicted to be impossible within a specific time in the Step S106 (N in Step S106), the time reporting unit 205 a executes actions from the Step S110 without informing the time required for reconnection.

[0103] In this way, when the line is connected between the portable telephone 221 and other telephone, the time reporting unit 205 a repeats actions from the Step S100 to the Step S110, and informs time allowed for communication and time required for reconnection every time the prediction result of the latest communication level is obtained from the prediction unit 204.

[0104] On the other hand, when the driver is making a hands-free call by connecting the telephone line between the portable telephone 221 and other telephone, the connection unit 205 b of the prediction processing unit 205 in this embodiment decides whether the line will be disconnected shortly or not according to the prediction result by the prediction unit 204. As a result of it, if the line is predicted to be disconnected soon, the connection unit 205 b instructs the control unit 213 to inform it of the telephone number of the telephone currently being connected to the portable telephone 221 through the telephone line in order to reconnect the line after the disconnection. The control unit 213 receiving such instruction obtains the telephone number of the above telephone currently on line from the portable telephone 221 via the portable telephone specific communicating unit 211, and informs the telephone number to the connection unit 205 b. Then, the connection unit 205 b holds the telephone number informed.

[0105] Additionally, as mentioned above, when the connection unit 205 b decides the line will be disconnected soon, it makes the display unit 206 display characters indicating the termination of the communication such as “The communication is terminated due to a deteriorating communication status”, and the speakers 231˜234 output a similar type of announcement indicating the communication termination by superimposing the announcement on the voice of the calling party. Furthermore, the connection unit 205 b makes the reporting signal showing the above announcement sent from the portable telephone 221 to the telephone of the calling party. As its result, the telephone of the calling party outputs the announcement indicating the above communication termination by superimposing it on the voice of the driver.

[0106] Then, the connection unit 205 b further instructs the control unit 213 to automatically terminate the communication.

[0107] The control unit 213 receiving such instruction of the automatic termination puts the portable telephone 221 on the hook by controlling the portable telephone specific communicating unit 211. As a result of it, the communication between the portable telephone 221 and the telephone is normally terminated.

[0108] After the communication is terminated, the connection unit 205 b obtains the detected position information from the position detecting unit 207, and repeats to readout the communication level corresponding to the position indicated in the detected position information from the communication status data 202 a. That is to say, the connection unit 205 b obtains the communication level at the current position. Then, the connection unit 205 b decides whether reconnection is currently possible or not. If decided to be possible, the connection unit 205 b, in stead of the operation unit 212, informs the telephone number held before the communication termination to the control unit 213, and sends a reconnection signal, which instructs to call the telephone of the telephone number, to the control unit 213. As its result, the control unit 213 has the portable telephone 221 call the telephone of the telephone number via the portable telephone specific communicating unit 211, and makes the telephone line be reconnected between the portable telephone 221 and telephone.

[0109] In this way, since the communication termination due to a deteriorating communication status is pre-informed, it is possible in the communication device 200 of this embodiment to prevent the communication from being disconnected suddenly. Also, the communication device 200 eliminates troublesome operations for the user and makes it easy to handle because it can automatically terminate communication and reconnect the line without relying on the user's operation when the communication status gets better. That is to say, through the announcement made by the above time reporting unit 205 a, or even when the user tries to continue his call without terminating the communication manually, it automatically terminates and reconnects the communication line as above so that it can further gets rid of the user's annoyance.

[0110] The following describes a series of actions taken by the connection unit 205 b in such prediction processing unit 205 with reference to FIG. 8.

[0111]FIG. 8 is an action flow diagram to show a series of actions taken by the connection unit 205 b.

[0112] At first, the connection unit 205 b obtains a prediction result of the communication level from the prediction unit 204 (Step S200). Then, the prediction unit 205 b predicts whether the line will be disconnected in the near future or not based on the prediction result (Step S202). For example, if the line is predicted to be disconnected after one minute (Y in Step S102), it obtains a telephone number of the telephone of the calling party and retains it (Step S204). Then, it informs the user and his calling party of the termination of the communication (Step S205). After it is informed, it terminates the communication automatically (Step S206).

[0113] Then, the connection unit 205 b obtains the communication level at the current position from the communication status data 202 a (Step S208), and decides whether it can reconnect it currently or not (Step S210). If it decides the reconnection is possible at this point (Y in Step S210), the connection unit 205 b informs the telephone number retained in the Step S204 to the control unit 213 and reconnects the telephone to the portable telephone 221 (Step S212). If it decides the reconnection is impossible (N in Step S210), the connection unit 205 b obtains the communication level at the current position once again and repeats actions from the Step S208.

[0114] In the steps S208 and S210 for the above example, it makes the connection unit 205 b decide whether the reconnection is possible or not based on the communication level of the communication status data 202 a, but its decision can also be made, for example, based on a measurement result of a radio wave intensity of the portable telephone 221.

[0115] Although the connection unit 205 b obtains the telephone number in the Step S204, it can obtain the telephone number of the calling party, for example, through the caller's ID notification service when receiving an incoming call or through the telephone number when making an outgoing call and can memorize it.

[0116] Also, the call regulation unit 205 c of the prediction processing unit 205 regulates incoming and outgoing calls of the portable telephone 221 even at a place in the good communication status if the automobile goes through the place in the good communication status only for a short time within an area in the bad communication status. In this way, the user's nuisances can be lightened because any calls disconnected shortly are prohibited.

[0117] As stated above, the following describes an example of the automobile which goes through the place in a good communication status just for a short time within a location in a bad communication status with reference to FIG.9.

[0118]FIG. 9 is an explanatory diagram to explain how the automobile goes through two tunnels.

[0119] As indicated in this FIG. 9, two tunnels ta and tb are closely located each other on a road. Also, the communication status is inferior in both tunnels ta and tb, but it is good at the place between the tunnels ta and tb. Therefore, when the automobile drives on such a road from the tunnel ta to the tunnel tb, the automobile is in a good communication status just for a little while when it goes through the place between the tunnels ta and tb.

[0120] Then, in a situation where the automobile is driving in a bad communication status, for example when it is driving in the tunnel ta in FIG. 9, and the telephone line is not being connected between the portable telephone 221 and other telephone, if the call regulation unit 205 c decides the automobile will reach at the place in the good communication status and the line can be connected within a specific time from the prediction result of the communication level from the prediction unit 204, and it further decides whether the time allowed for the line connection is shorter than a specific time (i.e. the minimum calling time). If the time allowed for line connection here is decided to be shorter than the minimum calling time, and when the automobile is actually traveling at the place in the good communication status, the call regulation unit 205 c outputs a regulation signal to the control unit 213, which instructs to respectively nullify: an outgoing call operation signal, which instructs to make an outgoing call to other telephone, output from the operation unit 212 to the control unit 213; an incoming call notification signal, which informs an incoming call from other telephone, output from the portable telephone 221 to the control unit 213 via the portable telephone specific communicating unit 211.

[0121] Also, if the call regulation unit 205 c is informed of a receipt of the above outgoing call operation signal from the control unit 213 when the regulation signal is output, it informs the user that the operation is nullified, i.e. the outgoing call is regulated, through the display unit 206 and the speakers 213˜234. And, if the call regulation unit 205 c is informed of a receipt of the above incoming call notification signal from the control unit 213 when the regulation signal is output, it makes the control unit 213 control the portable telephone specific communicating unit 211 and the portable telephone 221, and makes the speaker of other telephone, which is making the outgoing call to the portable telephone 221, output a message for the user of the telephone that the regulation for the incoming calls are regulated at the communication device 200 side.

[0122] The following describes an example of actions of such call regulation unit 205 c of the prediction processing unit 205 with reference to FIG. 10.

[0123]FIG. 10 is an action flow diagram to show the example of actions taken by the call regulation unit 205 c in a situation the automobile is driving at the area in the bad communication status and the telephone line is not connected between the portable telephone 221 and other telephone.

[0124] At first, the call regulation unit 205 c obtains a prediction result of the communication level from the prediction unit 204 (Step S300). Then, the call regulation unit 205 c predicts whether the line connection is possible based on the prediction result (Step S302). If it predicts the line connection is possible (Y in Step S302), it decides whether the time allowed for the line connection is shorter than the minimum calling time (Step S304). If it predicts the line connection is impossible (N in Step S302), the call regulation unit 205 c obtains the prediction result of the latest communication level once again and repeats actions from the Step S300.

[0125] When the time allowed for line connection is decided to be shorter than the minimum calling time in the Step S304 (Y in Step S304), the call regulation unit 205 c obtains the communication level at the current position by obtaining the detected position information from the position detecting unit 207 and reading out the communication level corresponding to the position indicated in the detected position information from the communication status data 202 a (Step S306). Then, the call regulation unit 205 c decides whether the line can be connected currently or not (Step S307).

[0126] If the line connection is decided to be possible currently (Y in Step S307), the call regulation unit 205 c outputs a regulation signal to the control unit 213 (Step S308). By doing so, the outgoing call operation signal from the operation unit 212 and the incoming call notification signal from the portable telephone 221 are nullified in the control unit 213. It results to regulate outgoing and incoming calls for the portable telephone 221. Also, if the line connection is decided to be impossible currently (N in Step S307), the connection unit 205 b obtains the communication level at the current location once again and repeats actions from the Step S306.

[0127] Next, when the regulation signal is output, the call regulation unit 205 c decides whether the outgoing call operation signal or the incoming call notification signal is received by the control unit 213 based on the notification from the control unit 213 (Step S310). Then, if the call regulation unit 205 c decides the outgoing call operation signal or the incoming call notification signal is received by the control unit 213 (Y in Step S310), the call regulation unit 205 c informs the user of this device and the user of the telephone, which is calling to the portable telephone 221, of the incoming and outgoing call regulation as stated above (Step S312).

[0128] Subsequently, the call regulation unit 205 c obtains the communication level at the current position in the same way as the Step S306 (Step S313), and decides whether the line can be connected or not currently (Step S314). When the line connection is decided to be impossible at this point (Y in Step S314), the call regulation unit 205 c stops the regulation signal output (Step S316). If the line connection is decided to be possible (N in Step S314), the call regulation unit 205 c repeats action from the Step S310. Also, in the Step S310, if the call regulation unit 205 c decides the outgoing call operation signal or the incoming call notification signal is not received by the control unit 213 (N in Step S310), the call regulation unit 205 c executes steps from the Step S313 without making notification in Step S312.

[0129] If the time allowed for line connection is the same as the minimum calling time or longer (N in Step S304), the call regulation unit 205 c maintains the status to stop regulation signal output (Step S318).

[0130]FIG. 11A is a screen display diagram to show an example of a screen displayed on the display unit 206 when the call regulation unit 205 c informs the regulation of outgoing calls to the user in the Step S312.

[0131] As shown in this diagram 11A, messages describing “You cannot make a call because communication status gets worse shortly” and “Predicted time allowed for call: 1 minute” and a release button shown as “Release regulation” are displayed in the display unit 206.

[0132] These messages and the release button are displayed by the call regulation unit 205 c making the control unit 213 control the display unit 206. Also, the time displayed in the message of “Predicted time allowed for call: 1 minute” (“1 minute” in this example) is depended on the time allowed for line connection decided by the call regulation unit 205 c in the Step S304 and on the time when the user performs the outgoing call operation. For example, if the time allowed for line connection is decided to be two minutes in the step S304, and the user performs the outgoing call operation one minute after the decision that the line connection is possible in the Step. 307, “Predicted time allowed for call: 1 minute” is displayed as indicated in FIG. 11A. If the user performs the outgoing call operation one minute and half after the decision that the line connection is possible in the Step S307, “Predicted time allowed for call: 30 seconds” is displayed.

[0133] If the user touches the release button displayed as “Release regulation”, the call regulation unit 205 c stops the regulation signal output. That is to say, the display unit 206 includes a function as a touching panel and is embodied in the same structure with the operation unit 212. The signal, which indicates activation of the release button, is obtained by the call regulation unit 205 c from the display unit 206 via the control unit 213. As its result, because output of the regulation signal is stopped as above, the control unit 213 treats the outgoing call operation signal from the operation unit 212 as valid so that it has the portable telephone 221 make the outgoing call.

[0134]FIG. 11B is a screen display diagram to show an example of a screen displayed in the display unit 206 when the call regulation unit 205 c informs the user of the incoming call regulation in the Step S312.

[0135] As shown in this FIG. 11B, messages such as “Receiving call, but cannot answer because communication status gets worse shortly” and “Predicted time allowed for call: 1 minute” and the release button indicated as “Release regulation”.

[0136] As explained in the above FIG. 11A, these messages and the release button are displayed by the call regulation unit 205 c making the control unit 213 control the display unit 206. Also, the time indicated in the message of “Predicted time allowed for call: 1 minute” (1 minute in the above example) is depended on the time allowed for line connection decided by the call regulation unit 205 c in the Step S304 and the time when an incoming call is received. And if the user touches the release button indicated as “Release regulation”, the call regulation unit 205 c stops the regulation signal output. As its result, the control Unit 213 treats the incoming call notification signal from the portable telephone 221 as valid, and makes the portable telephone 221 receive the incoming call.

[0137] The following explains characteristic actions of such communication device 200 in this embodiment with reference to FIG. 12.

[0138]FIG. 12 is an action flow diagram to show characteristic actions of the communication device 200 installed to the automobile in a process where the automobile goes through the areas in the good and bad communication statuses.

[0139] At first, when the automobile goes through the area in the good communication status, the communication device 200 connects the telephone line according to the user's operation (Step S400). As its result, the user starts a hands-free communication.

[0140] Next, when the automobile approaches the area in the bad communication status such as a tunnel, the communication device 200 predicts the line will be disconnected (Step S402) and informs the time allowed for connection to the user and his calling party (Step S403). Then, when the communication device 200 predicts the line will be connectable once again after the line connection (Step S404), it informs the time required for re-connection to the user and his calling party (Step S405).

[0141] Moreover, when the automobile goes to an area just before the tunnel, the communication device 200 retains the telephone number of the calling party's telephone and informs termination of the communication, and then automatically terminates the communication (Step S408).

[0142] When the automobile gets out from the tunnel and enters into the area in the good communication status, the communication device 200 reconnects the line to the telephone, which was connected before the tunnel (Step S410). In this way, the user can start his hands-free communication with the same calling party without operating the communication device 200. Also if the user operates the communication device 200 to end the communication, the communication device 200 terminates the communication with the above telephone according to the operation (Step S412).

[0143] Next, when the automobile enters into a tunnel once again, the communication device 200 is not in a communicational status. Then, the automobile approaches the end of the tunnel, the communication device 200 predicts the line can be connectable soon. But if there is another tunnel close to the current tunnel, the communication device 200 predicts the time allowed for line connection is less than the minimum calling time (Step S414). Therefore, even if the automobile gets out from the first tunnel and reaches the area in the good communication status located right before the aforementioned second tunnel, the communication device 200 regulates incoming and outgoing calls (Step S416). By doing so, the user does not make a call that may be disconnected soon so that it reduces the user's nuisances.

[0144] Subsequently, once the automobile goes into the aforementioned second tunnel, the communication device 200 de-regulates the above regulation since the automobile is in the bad communication status (Step S418).

[0145] In this way, the communication device 200 in this embodiment can lighten the user's annoyance even if the communication status is fluctuated by moving.

[0146] These are the explanations for the communication device related to the present invention with reference to the present embodiment, but the present invention is not limited to these.

[0147] For example, the position information is registered in the communication status data 202 a by using longitude and latitude in the present embodiment, but other description such as an address may be used for its registration. Additionally, though the communication level is graded into 10 different levels and registered into the communication status data 202 a, other description including a temporal average value of a radio wave density may be used in stead of the 10 level rating. Also, the present embodiment makes each of the time reporting unit 205 a in the prediction processing unit 205, the connection unit 205 b and the call regulation unit 205 c decide that the communication status gets worse and the line is disconnected when the communication level becomes “1”, and that the line can be connected when the communication level becomes “2” or more. However, a threshold value of such communication level may be something other than “1”. The above threshold value may also be changed if the user's operations of the operation unit 212.

[0148] Additionally, the communication device 200 in this embodiment is described as a hands-free device containing such a car navigation function, but the communication device 200 does not have to provide the car navigation function. That is to say, if there is a terminal for a car navigation system within the automobile, signals can be exchanged between the communication device 200 and the car navigation system. Or if there is no such a car navigation system within the automobile, it is possible to apply the method indicated in FIG. 5, i.e. making the communication device 200 predict its position after a certain time all the time based on the position, moving speed and moving direction of the automobile (the communication device 200). By doing so, the communication device 200 does not need to carry the map memory unit 201 or the navigation unit 203 so that the communication device 200 can be kept in a compact size. Additionally, the road information obtaining unit 210 may be removed from the communication device 200. In such a case, if there is a device to obtain the road traffic information in the automobile, the communication device 200 may exchange signals with the device. In this way, the size of the communication device 200 may be further reduced. Additionally, the communication device 200 may be structured as a portable telephone or an automobile phone.

[0149] Also, in this embodiment, the connection unit 205 b of the prediction processing unit 205 automatically terminates the communication before the communication device 200 goes into the area in the bad communication status, but the communication may be terminated after it enters into the area in the bad communication status.

[0150] It is also possible to specify the moving direction of the communication device 200 based on changes in the position through a time passage detected by the position detecting unit 207, though a moving direction of the communication device 200 in this embodiment is specified by making the direction detecting unit 208. In the same way as this, it is alternately possible to specify the moving speed of the communication device 200 based on changes in the moving speed through a time passage detected by the position detecting unit 207 rather than making the speed detecting unit 209 detect the moving speed of the communication device 200 through the circulation speed of the automobile's wheel as stated in this embodiment.

[0151] (Second Embodiment)

[0152] The following describes a communication system in the second embodiment of the present invention.

[0153]FIG. 13 is a structure diagram of the communication system 100 in the second embodiment of the present invention.

[0154] This communication system 100 is to reduce the user's nuisances of the mobile communication device in a situation the mobile communication device is moved via an area in a bad communication status such as a tunnel or a mountain area, which includes following elements: a portable telephone 130 as the above mobile communication device; three general telephones 140 a˜ 140 c respectively installed at each house; a base station 120 placed at a specific location to exchanges a radio wave as a wireless communication medium with the portable telephone 130; a communication line network 150 to connect the portable telephone 130 with each telephone 140 a˜ 140 c via the base station 120; and a server 110 to control communication between the portable telephone 130 and each telephone 140 a˜ 140 c.

[0155]FIG. 14 is a block diagram to show internal structures of the server 110 and the portable telephone 130 in the communication system 100 in this embodiment.

[0156] The portable telephone 130 is equipped with a display unit 131 including a microphone 138, a speaker 137 and a liquid crystal display, a modem 135 that sends and receives signals via the communication line network 150 and executes A/D conversions and D/A conversions for the sent and received signals, a CODEC unit 136 that compresses and decompresses data, the control unit 132 that controls these microphone 138 and speaker 137 or the like, buttons including a button to enter a telephone number and an operation unit 134 to output signals according to operations of these buttons to the control unit 132.

[0157] When the modem 135 is connected to each telephone 140 a˜ 140 c via the base station 120 and the communication line network 150, the control unit 132 of such portable telephone 130 collects the user's voice to the microphone 138, converts the portable telephone voice signal indicating the voice to A/D for the modem 135, and then sends the portable telephone voice signal to the telephone 140 a˜ 140 c being on-line. Then, when the modem 135 obtains a voice signal indicating the user's voice of the telephone 140 a˜ 140 c from the telephone 140 a˜ 140 c, the control unit 132 converts the voice signal to D/A and outputs it to the speaker 137. As a result of this, it makes it possible to communicate between the portable telephone 130 and the telephone 140 a˜ 140 c being connected to the line. Each of the portable telephone signal and the voice signal mentioned above are sent and received between the portable telephone 130 and any of the telephones 140 a˜ 140 c.

[0158] The portable telephone 130 additionally includes following elements: a position detecting unit 133 a that detects its own position by obtaining GPS data indicating a position from a GPS satellite; a direction detecting unit 133 b that detects a moving direction of the portable telephone 130 based on a detected result of the position detecting unit 133 a; and a speed detecting unit 133 c that detects a moving speed of the portable telephone 130 based on the detected result of the position detecting unit 133 a.

[0159] The position detecting unit 133 a detects its own position, for example “135° 25′ 30 east longitude, 40° 30′ 25″ north latitude”, per specific time such as in every 5 seconds or in every 1 minute, and outputs the detected position information indicating the detected result.

[0160] The direction detecting unit 133 b obtains the detected position information from the position detecting unit 133 a, detects a moving; direction of the portable telephone 130 based on changes in the position per specific time indicated in the detected position information, and outputs direction information indicating the detected moving direction.

[0161] The speed detecting unit 133 c obtains the detected position information from the position detecting unit 133 a, detects a moving speed of the portable telephone 130 from changes in the position per specific time indicated in the detected position information, and outputs speed information indicating the detected moving speed.

[0162] As stated above, the control unit 132 of the portable telephone 130 obtains the detected position information, direction information and speed information from the position detecting unit 133 a, the direction detecting unit 133 b and the speed detecting unit 133 c, and sends prediction material data including these information from the modem 135 to the server 110. These prediction material data is sent per specific time or per specific distance based on the latest detected result output from the position detecting unit 133 a, the direction detecting unit 133 b and the speed detecting unit 133 c. Also, according to changes in the communication status, the latest prediction material data may be sent from the portable telephone 130. When the communication status is changed drastically, it is possible to have the portable telephone 130 send the latest prediction material data frequently.

[0163] The server 110 comprises following elements: a communication unit 113 that sends and receives signals between the portable telephone 130 and each telephone 140 a˜ 140 c via the communication line network 150; a map memory unit 116 that memorizes map data 116 a indicating a map in advance; a communication status storage unit 117 that stores communication status data 117 a showing a communication status at each position on the map; a navigation unit 119 that obtains detected position information contained in the prediction material data received at the communication unit 113 from the portable telephone 130 and that creates navigation data including information necessary for navigating the user from the position indicated in the detected position information to a destination specified by the user of the portable telephone 130; a road information obtaining unit 112 that obtains road traffic information such as through VICS (Vehicle Information Communication System); a prediction unit 114 that estimates a position of the portable telephone 130 after a specific time based on the prediction material data received at the communication unit 113 from the portable telephone 130 and that predicts a communication status at the predicted position with reference to the communication status data 117 a; a prediction data storage unit 118 that stores prediction data 118 a showing a prediction result by the prediction unit 114; a prediction processing unit 115 that execute each process such as a communication connection process based on the prediction data 118 a; and a server control unit 111 that controls each of the above units. The prediction processing 115 further includes a time reporting unit 115 a and a connection unit 115 b, and a call regulation unit 115 c, which are explained later. The server control unit 111, the prediction unit 114 and the prediction processing unit 115 here are constructed in CPU (Central Processing Unit), while the map data storage unit 116, the communication status storage unit 117 and the prediction data storage unit 118 are structured in ROM (Read Only Memory) or RAM (Random Access Memory).

[0164] The road obtaining unit 112 obtains road traffic information distributed from the VICS center. This road traffic information contains content informing traffic conditions of each road, etc.

[0165] When the navigation unit 119 obtains a navigation request signal that instructs to navigate the user to the destination and the above detected position information from the portable telephone 130 via the communication unit 113 and the server control unit 111, it reads out the map data 116 a covering the position indicated in the detected position information to the destination indicated in the navigation request signal from the map memory unit 116. The navigation unit 119 searches a route from the position indicated in the detected position information to the destination. At this point, the navigation unit 119 obtains the road traffic information from the road information obtaining unit 112 via the server control unit 111, and searches a route to reach the destination in a quickest way or in a shortest distance along with consideration of traffic conditions, etc. indicated in the road traffic information. Then, the navigation unit 119 outputs navigation data indicating the detected route and the current position of the portable telephone 130 on the map. The navigation data output in such a way is sent by the server control unit 111 from the communication unit 113 to the portable telephone 130. As a result of this, the map showing the current position of the portable telephone 130 and its surrounding area and the searched route are displayed on the display unit 131 of the portable telephone 130. The speaker 137 of the portable telephone 130 outputs a guiding voice such as “Please turn left at a next crossing”. By doing so, the user of the portable telephone 130 can recognize the current position and the route from the current position to the destination. If the user sits next to a driver of the automobile, he can navigate the driver according to the route.

[0166]FIG. 15 is a data content diagram to show content of the communication status data 117 a.

[0167] As shown in this diagram 15, the communication status data 117 a contains a position information field A11 and a communication level A12. In the position information field A11, position information is registered to indicate each position such as “longitude X1, latitudes Y1” or “longitude X2, latitudes Y2”. The communication level field A12, the communication level at the position indicated in the position information is shown. This communication level is to indicate a communication status, for instance, at 10 difference levels showing the communication level “1” for the worst communication status whereas the communication level “10” for the best communication status. For example, as shown in the FIG. 15, in the communication status data 117 a, the position at “longitude X1, latitudes Y1” is registered to be the worst status while the position at “longitude X3, latitudes Y3” is registered to be the best status. The prediction unit 114 estimates the position of the portable telephone 130 after a specific time by using the same method as explained for the FIG. 5 in the first embodiment.

[0168] Based on the prediction material data from the portable telephone 130, the prediction unit 114 decides, for example as shown in the FIG. 5, the portable telephone 130 is currently located at the position of P0 and is moving to a south-east direction as indicated by a solid arrow in the FIG. 5 at approx. 40 [km/hr].

[0169] Then, the prediction unit 114 estimates, for example after 1 minute, the portable telephone 130 will be located at the position of P1 after moving a distance of 40×1/60[km] to the south-east direction from the position of P0.

[0170] Furthermore, the prediction unit 114 searches the position information indicating the position of P1 from the communication status data 117 a memorized in the communication status storage unit 117. For example, when the position of P1 is at “longitude X2, latitudes Y2”, the prediction unit 114 reads out the communication level “9” corresponded to the position information indicating “longitude X2, latitudes Y2” from the communication status data 117 a, and predicts the communication level after 1 minute will be “9”.

[0171] In this way, the prediction unit 114 predicts the communication level after a specific time. For example, it predicts the communication level after 1 minute, 2 minutes, 3 minutes . . . and so on.

[0172] Also, when a route for the destination is searched by the navigation unit 119 and navigation data is sent to the portable telephone 130, the prediction unit 114 estimates the position of the automobile after a specific time by using the same method as explained for FIG. 6 in the first embodiment.

[0173] That is to say, the prediction unit 114 recognizes the current position of the portable telephone 130 on the searched route based on the navigation data, and estimates the position of the portable telephone 130 after a specific time along with the searched route based on the speed information contained in the prediction material data. For example as indicated in FIG. 6, the prediction unit 114 estimates, from the moving speed at the current position P00 on the searched route, the portable telephone 130 will be located at the position of P01 on the searched route after 1 minute, at the position of P02 after 2 minutes and at the position of P03 after 3 minutes.

[0174] Here, the prediction unit 114 takes accounts of road traffic information obtained by the road information obtaining unit 112 in estimating the position of the portable telephone 130 after a specific time. That is to say, when the portable telephone 130 is located on an automobile exclusive road or the like, the prediction unit 114 decides the portable telephone 130 is brought into the automobile. Then, when the road traffic information indicates the traffic at the position ahead on the searched route is busier than the current position, the prediction unit 114 assumes the portable telephone 130 is moved slower (for example, 20 km/hr) for the busier area than the moving speed at the current position (for example, 40 km/hr) and estimates the position of the portable telephone 130 after a specific time. Also, if the road traffic information indicates the location ahead on the searched route has less traffic than the current position, the prediction unit 114 assumes the portable telephone 130 is moved faster (for example 60 km/hr) for the location than the moving speed at the current position (for example 40 km/hr), and estimates the position of the portable telephone 130 after the specific time. By using the road traffic information in this way, the prediction unit 114 can estimate the location of the portable telephone 130 more accurately and estimate more precise communication level.

[0175] Additionally, information related to a speed limit for each road (speed limit information) is included in the map data 116 a memorized in the map memory unit 116. Therefore, the prediction unit 114 takes account of the speed limit information contained in the map data 116 a in estimating the position of the portable telephone 130 after a specific time. That is to say, in the above example, in a situation the moving speed in the location ahead on the searched route is presumed to be at 60 km/hr based on the road traffic information at the present location where the moving speed of the portable telephone 130 is at 40 km/hr, if the speed limit on the road ahead is indicated as 50 km/hr in the speed limit information, the prediction 114 assumes the moving speed will be 50 km/hr and estimates the position of the portable telephone 130 after a specific time. By using the speed limit information in this way, the prediction 114 estimates the position of the portable telephone 130 more accurately and predicts more precise communication level.

[0176] Then, the prediction 114 makes the prediction data storage unit 118 store the predicted result as prediction data 118 a.

[0177]FIG. 16 is a data content diagram to show content of the prediction data 118 a.

[0178] As indicated in the FIG. 16, the prediction data 118 a has a time information field B1 and a communication level field B2. Time information indicating time such as “after 1 minute” or “after 2 minutes” is registered in the time information field B1, while a communication level at the time shown in the time information is registered in the communication level field B2. That is to say, the communication level “after 1 minute” is “1” and the communication level “after 2 minutes” is “3” are registered in the prediction data 118 a shown in the FIG. 16.

[0179] Also, every time the prediction material data is obtained from the portable telephone 130, the prediction 114 conducts prediction such as above based on the latest prediction material data and updates the prediction data 118 a.

[0180] In the above explanation, the prediction 114 predicts future communication level in every 1 minute such as after 1 minute, 2 minutes, 3 minutes . . . and so on, but its time interval is not only limited to 1 minute, it may be every 10 seconds or something else. Also, its time interval may be longer or shorter according to changes in the communication status.

[0181] The prediction processing unit 115 includes following elements: a time reporting unit 115 a that reports the user of the portable telephone 130 and his calling party on the time allowed for communication, etc. based on the communication level predicted by the prediction 114, i.e. the prediction data 118 a stored in the prediction data storage unit 118; a connection unit 115 b that instructs the server control unit 111 to conduct a connection process between the portable telephone 130 and each telephone 140 a˜ 140 c via the communication line network 150 when the portable telephone 130 goes through the area in a bad communication status, and a call regulation unit 115 c that regulates incoming and outgoing calls of the portable telephone 130 when the portable telephone 130 goes through the place in a good communication status only for a short time within the area in the bad communication status.

[0182] In a situation a communication line is connected between the portable telephone 130 and any of the telephones 140 a˜ 140 c and each of the users communicating on the phones, if the time reporting unit 115 a decides, based on the prediction data 118 a, wireless communication between the portable telephone 130 and a base station 120 will be disconnected because the portable telephone 130 will reach the area in the bad communication status, it informs the user of the portable telephone 130 and his calling party of the communication time (time allowed for communication) allowed until the portable telephone 130 reaches the area. If content, for example the communication level is “9” after 1 minute, “8” after 2 minutes, “5” after 3 minutes, “1” after 4 minutes, is registered in the prediction data 118 a, the time reporting unit 115 a decides the portable telephone 130 will reach the area in the bad communication status after 4 minutes and the wireless communication will be disconnected, and creates reporting data indicating its decision result. Then, the time reporting unit 115 a outputs the reporting data to the server control unit 111, makes the server control unit 111 control the communication unit 113, and makes the communication unit 113 send the reporting data to the portable telephone 130 and the calling party's telephone 140 a˜ 140 c. As a result of it, when the control unit 132 of the portable telephone 130 obtains the reporting data via the modem 135, it makes the display unit 131 display a message such as “The line will be disconnected after 4 minutes” and makes the speaker 137 output an announcement such as “The line will be disconnected after 4 minutes due to the deteriorating communication status” by superimposing it on a voice of the calling party. Furthermore, in the same way as the above the portable telephone 130, when the telephone 140 a˜ 140 c obtains the reporting data, it displays some message as above, and outputs the above announcement by superimposing it on the voice of the user of the portable telephone 130.

[0183] In this way, it is possible in the communication system 100 of this embodiment to avoid sudden line disconnection, the user of the portable telephone 130 and the user of each telephone 140 a˜ 140 c can recognize in advance when the line is disconnected.

[0184] Additionally in a situation the communication line is connected between the portable telephone 130 and any of the telephones 140 a˜ 140 c and each user is on the phone, if the time reporting unit 115 decides, based on the prediction data 118 a, the wireless communication between the portable telephone 130 and the base station 120 will be disconnected because the portable telephone 130 reaches at the area in the bad communication status after a specific time and later the portable telephone 130 will get out from the area in the bad communication status and the wireless communication will become possible again, the time reporting unit 115 reports the user of the portable telephone 130 and his calling party on the time allowed for the communication as above and the time required for the line reconnection (time required for reconnection).

[0185] For example, as stated above, if content, such as the communication level is “5” after 3 minutes, “1” after 4 minutes, “2” after 10 minutes, is registered in the prediction data 118 a, the time reporting unit 115 a decides the wireless communication will be disconnected based on the prediction data 118 a because the portable telephone 130 reaches the area in the bad communication status after 4 minutes, and then, the wireless communication will become possible again when the portable telephone 130 gets out from the location in the bad communication status after 10 minutes. Then, the time reporting unit 115 a creates reconnection reporting data to show the decision result as above, outputs the reconnection reporting data to the server control unit 111, has the server control unit 111 control the communication unit 113, and makes the communication unit 113 send the reconnection reporting data to the portable telephone 130 and the telephone 140 a˜ 140 c of the calling party.

[0186] As a result of it, when the control unit 132 of the portable telephone 130 obtains the reconnection reporting data via the modem 135, it makes the display 131 display characters such as “It is possible to reconnect the line after 10 minutes”, and makes the speaker 137 output an announcement such as “It is possible to reconnect the line after 10 minutes” with superimposing it on a communication voice of the calling party. Additionally, in the same way as the portable telephone 130, when the telephone 140 a˜ 140 c obtains the reconnection reporting data, it displays the above message and outputs the above announcement by superimposing it on the user's voice of the portable telephone 130.

[0187] In this way, it is possible in the communication system 100 of this embodiment for the user of the portable telephone 130 and his calling party communicating on the phone to know the time required for reconnection. Because it makes it easy to handle for the users, nuisances of the user and his calling party are removed because.

[0188] The following describes a series of actions taken by the time reporting unit 115 a of the prediction processing unit 115 such as above with reference to FIG. 17.

[0189]FIG. 17 is an action flow diagram to show a series of actions taken by the time reporting unit 115 a when a communication line is connected between the portable telephone 130 and the telephone 140 a.

[0190] At first, the time reporting unit 115 a obtains the prediction data 118 a from the prediction data storage unit 118 (Step S500). Then, the time reporting unit 115 a predicts whether the wireless communication is disconnected or not based on the prediction data 118 a (Step S502). If the wireless communication is predicted to be disconnected after 5 minutes (Y in the Step S502), it creates the reporting data and reports the user of the portable telephone 130 and his calling party on the time allowed for communication (5 minutes) (Step S504). And if the wireless communication is predicted not to be disconnected in the Step S502 within a specific time (N in the Step S502), the time reporting unit 115 a repeats to obtain the latest prediction data 118 a from the prediction data storage unit 118 and repeats actions from the Step S500.

[0191] Moreover, when the time reporting unit 115 a predicts the wireless communication will be disconnected in the Step S502, it further predicts whether the wireless communication will be possible again or not within a specific time based on the prediction data 118 a (Step S506). As a result of it, if the time reporting unit 115 a predicts the wireless communication is possible after 9 minutes (Y in the Step S506), it creates the reconnection reporting data and informs the user of the portable telephone 130 and his calling party of the time required for reconnection (9 minutes) (Step S508). Then, if the time reporting unit 115 a recognizes the line is actually disconnected via the server control unit 111, it terminates the process (Y in the Step S510). If the line is not disconnected (N in the Step S510), it repeats actions from the Step S500 once again.

[0192] As a result of it, until the wireless communication is disconnected, announcements, such as “The line will be disconnected after 5 minutes due to the poor communication status” and “Reconnection is possible after 9 minutes”, and one minute later, “The line will be disconnected after 4 minutes due to the poor communication status” and “Reconnection is possible after 8 minutes” and so on, are repeatedly is output from the portable telephone 130 and the telephone 140 a of his calling party.

[0193] Also, if the wireless communication is predicted to be impossible within the specific time in the Step S506 (N in the Step S506), the time reporting unit 115 a executes actions from the Step S510 without informing the time required for reconnection.

[0194] In this way, when the communication line is connected between the portable telephone 130 and one of the telephones 140 a˜ 140 c, the time reporting unit 115 a repeats actions from the Step S500 to the Step S510, and reports on the time allowed for communication and the time required for reconnection based on the result whenever the latest prediction data 118 a is obtained by the prediction data storage unit 118.

[0195] On the other hand, in a situation each of the users are communicating through the communication line connected between the portable telephone 130 and one of the telephones 140 a˜ 140 c, if the connection unit 115 b of the prediction processing unit 115 in this embodiment decides the wireless communication will be disconnected in the near future, it decides whether the time not allowed for communication is the same as or less than the maximum holding time.

[0196] At this point, when the connection unit 115 b decides the time not allowed for communication is same as or less than the maximum holding time, it maintains the communication between the telephone 140 a˜ 140 c, which is a calling party of the portable telephone 130, and the server 110, and puts the telephone 140 a˜ 140 c on hold even if the wireless communication is disconnected between the portable telephone 130 and the base station 120. Then, when the connection unit 115 b decides the portable telephone 130 can make the wireless communication, it connects the line once again between the portable telephone 130 and the telephone 140 a˜ 140 c being on hold.

[0197] To be more specific, when the connection unit 115 b decides the time not allowed for communication is the same as or less than the maximum holding time, it instructs the server control unit 111 to make it informed of the telephone number of the portable telephone 130 to reconnect the line after the wireless communication is disconnected. The server control unit 111 receiving such an instruction, obtains the telephone number from the portable telephone 130 via the communication unit and informs the telephone number to the connection unit 115 b. Then, the connection unit 115 b retains the telephone number notified.

[0198] Moreover, the connection unit 115 b creates termination reporting data indicating communication termination such as “The communication is terminated due to the bad communication status”, and outputs it to the server control unit 111, makes the server control unit 111 control the communication unit 113, and makes the communication unit 113 send the communication termination data to the portable telephone 130.

[0199] As a result of it, if the control unit 132 of the portable telephone 130 obtains the termination reporting data via the modem 135, it makes the display unit 131 display characters such as “The communication will be terminated due to the poor communication status”, and makes the speaker 137 output an announcement such as ““The communication will be terminated due to the poor communication status” by superposing it on the communication voice of the calling party.

[0200] In addition, the connection unit 115 b instructs the server control unit 111 to terminate the communication automatically. The server control unit 111 receiving such instruction of automatic termination has the communication unit 113 put the portable telephone 130 on the hook by controlling the communication unit 113. As a result of it, the communication between the portable telephone 130 and the server 110 is terminated normally.

[0201] Then, even when the communication between the communication unit 113 of the server 110 and the portable telephone 130 is automatically terminated, the connection unit 115 b maintains the communication between the communication unit 113 of the server 110 and the telephone 140 a˜ 140 c, which is a calling party of the portable telephone 130. In the meantime the communication is maintained, the connection unit 115 b creates holding notification data indicating “holding”, makes the server control unit 111 control the communication unit 113, and makes the communication unit 113 send the holding notification data to the telephone 140 a˜ 140 c. As a result of it, when the telephone 140 a˜ 140 c obtains the holding notification data, it outputs an announcement such as “It is suspended. Please wait” until the line is reconnected with the portable telephone 130. That is to say, the telephone 140 a˜ 140 c is put on hold.

[0202] Furthermore, after the telephone 140 a˜ 140 c is put on hold as above, if the connection unit 115 b decides the portable telephone 130 gets out from the area in the bad communication status, it makes the communication unit 113 to resume the communication with the portable telephone 130 via the server control unit 111 by using the telephone number retained before the line disconnection. Then, the connection unit 115 b releases the holding status of the telephone 140 a˜ 140 c and makes it possible to communicate with the telephone 140 a˜ 140 c. In short, the communication line between the portable telephone 130 and the telephone 140 a˜ 140 is reconnected.

[0203] In this way, because the communication termination due to the bad communication status is reported in advance in the communication system 100 of this embodiment, it can avoid sudden disconnection of the line. Since the communication is automatically terminated and reconnected when the communication status gets better without requiring the user's operation of the portable telephone 130, it reduces the user's nuisances of the portable telephone 130 and improves easiness of the use. That is to say, even through the report by the above time reporting unit 115 a or even when the user continues his communication without terminating the communication manually, it is automatically terminated and reconnected as above so that it further reduces the nuisances of the user. Also, if the time not allowed for communication is short, the telephone 140 a˜ 140 c which has been communicating with the portable telephone 130 is put on hold, it does not require the user of the telephone 140 a˜ 140 c to put the telephone 140 a˜ 140 c on the hook so that it reduces such a useless action of the user.

[0204] The following describes a series of actions taken by the connection unit 115 b of such prediction processing unit 115 with reference to FIG. 18.

[0205]FIG. 18 is an action flow diagram to show a series of actions taken by the connection unit 115 b.

[0206] At first, the connection unit 115 b obtains prediction data 118 a (Step S600), and predicts whether the wireless communication between the portable telephone 130 and the base station 120 will be disconnected shortly or not (Step S602). Then, if the connection unit 115 b predicts it will be disconnected shortly (Y in the Step S602), it decides whether the time not allowed for communication is the same as or less than the maximum holding time or not (Step S604). If it predicts it will not happen shortly (N in the Step S602), it repeats actions from the Step S600.

[0207] When specifying the time not allowed for communication in the Step S604, if the connection unit 115 b decides an interval from one occasion of the time not allowed for communication to a next occasion of the time not allowed for communication is extremely short, the connection unit 115 b also regards the interval as the time when the communication should not be allowed, and combines these time duration to specify them as the time not allowed for communication. In this way, the connection unit 115 b can avoid a troublesome connection process.

[0208] Next, when the connection unit 115 b decides the time not allowed for communication is the same as or less than the maximum holding time (Y in the Step S604), it obtains the telephone number from the portable telephone 130 via the server control unit 111 and the communication unit 113 (Step S606), and reports the user of the portable telephone 130 and his calling party on the communication termination (Step S608). Then, the connection 115 b automatically terminates the communication between the communication unit 113 and the portable telephone 130 and puts the telephone 140 a˜ 140 c, which is a calling party of the portable telephone 130, on hold (Step S610). On the other hand, if the time not allowed for communication is decided to be longer than the maximum holding time, or if the time not allowed for communication is decided to be unpredictable from the prediction data 118 a (N in the Step S604), the connection unit 115 b sends the termination reporting data from the communication unit 113 to the portable telephone 130 and the telephone 140 a˜ 140 c of the calling party, and reports on the communication termination to the user of the portable telephone 130 and his calling party (Step S618). Then, the connection unit 115 b makes the server control unit 111 control the communication unit 113, and automatically terminates the communication between the communication unit 113 and the portable telephone 130, and also the communication between the communication unit 113 and the telephone 140 a˜140, which is a calling party of the portable telephone 130 (Step S620).

[0209] Next, the connection unit 115 b obtains a communication level at the current position of the portable telephone 130 by obtaining the detected position information contained in the prediction material data after the Step S610, and reading out the communication level corresponding to the position indicated in the detected position information from the communication status data 117 a (Step S612). Then, the connection unit 115 b decides whether the wireless communication is possible for the portable telephone 130 currently or not based on the communication level (Step S614). As a result of it, if the wireless communication is decided to be possible (Y in the Step S614), the connection 115 b makes the communication unit 113 resume the communication with the portable telephone 130 via the server control unit 111, and reconnects the communication line between the portable telephone 130 and the telephone 140 a˜ 140 c, which has been the calling party (Step S616). Here, the connection unit 115 confirms whether the reconnection is done or not, and repeats to reconnect it if not. Then, if the reconnection is not successfully made after several times of its trials or after a specific time, the connection unit 115 gives up the reconnection process.

[0210] Also, if the wireless communication is decided to be impossible for the portable telephone 130 in the step S614 (N in the Step S614), actions from the Step S612 are repeated.

[0211] The call regulation unit 115 c of the prediction processing unit 115 regulates incoming and outgoing calls of the portable telephone 130 when the portable telephone 130 goes through a place in a good communication status just for a short time while driving through the area in the bad communication status. In this way, sudden disconnection of the communication is prevented so that nuisances that the user of the portable telephone 130 and the user of the telephone 140 a˜ 140 c who made a call to the portable telephone 130 can be reduced.

[0212] The following describes an example that the portable telephone 130 goes through the location where the communication status changes as above with reference to FIG. 19.

[0213]FIG. 19 is an explanatory diagram to describe how an automobile in which the portable telephone 130 is brought drives through two tunnels.

[0214] As shown in this FIG. 19, there are two tunnels ta and tb that are closely located each other on a road. Also, a communication status is bad in both tunnels ta and tb, whereas the area between the tunnels ta and tb has a good communication status. Therefore, if the automobile drives the road from the tunnel ta to the tunnel tb, the automobile gets a good communication status just for a short time when it travels the distance between the tunnels ta and tb.

[0215] In a situation the automobile goes through the area in the bad communication status, for example, drives in the tunnel ta in the FIG. 19, and a communication line is not connected between the portable telephone 130 and one of the telephones 140 a˜ 140 c, and if the call regulation unit 115 c decides the wireless communication will be possible because the portable telephone 130 will reach the area in the good communication status within a specific time, it further decides whether the time allowed for wireless communication is shorter than the minimum calling time or not. When the time allowed for the wireless communication is decided to be shorter than the minimum calling time, the call regulation unit 115 c subsequently decides whether or not the portable telephone 130 is currently traveling in the area in the good communication status. If yes, the call regulation unit 115 c regulates incoming and outgoing calls of the portable telephone 130. That is to say, the call regulation unit 115 c outputs the server control unit 111 a regulation signal instructing to nullify signals: an outgoing operation signal instructing to connect one of the telephones 140 a˜ 140 c sent from the portable telephone 130 to the server 110; and an incoming call notification signal instructing to connect to the portable telephone 130 sent from one of the telephones 140 a˜ 140 c to the server 110. In this way, even if the server control unit 111 receives the outgoing operation signal and the incoming call notification signal via the communication unit 113, it nullifies them so that incoming and outgoing calls for the portable telephone 130 are regulated.

[0216] Also, if the call regulation unit 115 receives a notification of receiving the above outgoing call operation signal from the server control unit 111 when outputting the regulation signal, it informs the user of the portable telephone 130 that the signal is being nullified, i.e. the outgoing call from the portable telephone 130 is regulated, through the display unit 131 and the speaker 137 of the portable telephone 130. That is to say, the call regulation unit 115 c creates an outgoing call regulation notification signal that informs outgoing calls are regulated from the portable telephone 130, and makes the communication unit 113 send it to the portable telephone 130 via the server control unit 111. Then, the control unit 132 of the portable telephone 130 receiving this outgoing call regulation notification signal via the modem 135 makes the display unit 131 display the content indicated in the outgoing call regulation notification signal as well as making the speaker 137 output the content.

[0217] Additionally, if the call regulation unit 115 c receives a notification of receiving the above incoming call notification signal when the regulation signal is output, it informs the user of the telephone 140 a˜ 140 c, which sent the incoming call notification signal, that of the signal is nullified, i.e. the incoming call to the portable telephone 130 is regulated. That is to say, the call regulation unit 115 c creates the incoming call regulation notification signal to inform that the incoming call to the portable telephone 130 is regulated, and makes the communication unit send this to the telephone 140 a˜ 140 c via the server control unit 111. Then, the telephone 140 a˜140 c receiving this incoming call regulation notification signal makes the speaker 137 output the content indicated in the incoming call regulation signal.

[0218] The following describes an example of actions taken by such a call regulation unit 115 c of the prediction processing unit 115 with reference to FIG. 20.

[0219]FIG. 20 is an action flow diagram to show an example of actions taken by the call regulation unit 115 c in a situation the portable telephone 130 is traveling in the area in the bad communication status and a communication line is not connected between the portable telephone 130 and the telephone 140 a˜ 140 c.

[0220] At first, the call regulation unit 115 c obtains the prediction data 118 a (Step S700), and predicts whether the wireless communication is possible between the portable telephone 130 and the base station 120 based on the prediction data 118 a (Step S702). Then, if the wireless communication is predicted to be possible (Y in the Step S702), it decides whether the time allowed for the wireless communication is shorter than the minimum calling time (Step S704). If the wireless communication is predicted to be impossible (N in the Step S702), the call regulation unit 115 c repeats actions from the Step S700 and obtains the prediction data 118 a once again.

[0221] Next, if the time allowed for the wireless communication is decided to be shorter than the minimum calling time in the Step S704 (Y in the Step S704), the call regulation unit 115 c obtains a communication level at the current position of the portable telephone 130 by obtaining the detected position information contained in the prediction material data and reading out the communication level corresponding to the position indicated in the detected position information (Step S706). Then, the call regulation unit 115 c decides the wireless communication is currently possible for the portable telephone 130 based on the communication level (Step S710). Here, if the wireless communication is decided to be possible (Y in the Step S710), the call regulation unit 115 c outputs a regulation signal and nullifies incoming and outgoing calls of the portable telephone 130 (Step S712). If the wireless communication is decided to be impossible (N in the Step S710), it obtains the latest prediction data 118 a and repeats actions from the Step S706 once again. Also, if the time allowed for the wireless communication is decided to be the same as or longer than the minimum calling time in the Step S704 (N in the Step S704), the call regulation unit 115 c keeps stopping the regulation signal output and allows the incoming and outgoing calls for the portable telephone 130 (Step S708).

[0222] Then, after the Step S712, i.e. when the regulation signal is output, the call regulation unit 115 c decides whether the outgoing call operation signal or the incoming call notification signal is received at the server control unit 111 according to a notification from the server control unit 111(Step S714). Then, if the call regulation unit 115 c decides the outgoing call operation signal or the incoming call notification signal is received by the server control unit 111 (Y in the Step S714), the call regulation unit 115 c outputs an outgoing call regulation notification signal or an incoming call regulation notification signal, and informs the user of the portable telephone 130 and the user of the telephone 140 a˜ 140 c, which sent the incoming call notification signal, that the incoming and outgoing calls for the portable telephone 130 (Step S716) are regulated as above.

[0223] Next, after the Step S716, or when the outgoing call operation signal or the incoming call notification signal is decided not to have been received in the Step S714 (N in the Step 714), the call regulation unit 115 c obtains a communication level at the current position of the portable telephone 130 (Step S718) once again, and decides whether the wireless communication for the portable telephone 130 is currently impossible or not based on the communication level (Step S720). Here, if the wireless communication is decided to be impossible currently (Y in the Step S720), the call regulation unit 115 c stops the regulation signal being output from the Step S712, and cancels nullification of incoming and outgoing calls of the portable telephone 130 (Step S722). If the wireless communication is decided to be possible currently (N in the Step S720), the call regulation unit 115 c repeats actions from the Step S714 again.

[0224]FIG. 21A is a screen display diagram: to show an example of a screen indicated in the display unit 131 when the call regulation unit 115 c informs the user of the portable telephone 130 that the outgoing calls are regulated in the Step S716.

[0225] As indicated in this FIG. 21A, messages such as “You cannot make a call because communication status gets worse shortly”, “Predicted time allowed for call: 1 minute” and “Press 1 to release regulation” are displayed in the display unit 131.

[0226] These messages are displayed in the display unit 131 controlled by the control unit 132 of the portable telephone 130 based on the outgoing call regulation notification signal. That is to say, the call regulation unit 115 c calculates the time allowed for communication according to the time allowed for the wireless communication decided in the Step S704 and the time duration from a point the wireless communication is decided to be possible in the Step S704 to the point the outgoing operation signal is received in the Step S714, and includes information indicating the predicted time allowed for communication in the outgoing call regulation notification signal. As a result of it, the message of “Predicted time allowed for call: 1 minute” is displayed in the display unit 131 of the portable telephone 130. For example, for the case the time allowed for the wireless communication is decided to be 2 minutes in the Step S704, and the time duration is 1 minute from the point the wireless communication is decided to be possible in the Step S710 to the point the outgoing call operation signal is received in the Step S714, “Predicted time allowed for call: 1 minute” as indicated in the FIG. 21A is displayed. Also, if it is 1 minute and half from the wireless communication is decided to be possible in the Step S710 to the point the outgoing call operation signal is received in the Step S714, “Predicted time allowed for call: 30 seconds” is displayed.

[0227] Here, if the user of the portable telephone 130, who sees the message of “Press 1 to release regulation” presses the button “1” on the operation unit 134, the control unit 132 of the portable telephone 130 makes the modem 135 send a release signal instructing to cancel the regulation to the server 110. Then, when the call regulation unit 115 c receives the release signal via the communication unit 113 and the server control unit 111, it stops the regulation signal output. As a result of it, since the output of the regulation signal is stopped, the server control unit 111 regards the outgoing call operation signal from the portable telephone 130 as valid, and the outgoing call regulation of the portable telephone 130 is canceled.

[0228]FIG. 21B is a screen display diagram to show an example of a screen indicated in the display unit 131 when regulation of the incoming call for the call regulation unit 115 c is informed to the user of the portable telephone 130 in the Step S716.

[0229] As shown in this diagram 21B, messages such as “Receiving call, but cannot answer because communication status gets worse shortly” “Predicted time allowed for call: 1 minute” and “Press 2 to release regulation”.

[0230] These messages are displayed by the control unit 132 of the portable telephone 130 controlling the display unit 131 based on the incoming call regulation signal. That is to say, the call regulation unit 115 c calculates the time allowed for communication according to the time allowed for the wireless communication decided in the Step S704 and the time duration from the point the wireless communication is decided to be possible in the Step S710 to the point the incoming call notification signal is received in the Step S714, and includes information indicating the predicted time allowed for communication in the incoming call regulation signal. As a result of it, the message of “Predicted time allowed for call: 1 minute” is displayed in the display unit 130 of the portable telephone 130.

[0231] If the user of the portable telephone 130 who sees the message of “Press 2 to release regulation” presses the button “2” on the operation unit 134, the control unit 132 of the portable telephone 130 makes the modem 135 send the release signal instructing to cancel the regulation to the server 110. Then, when the call regulation unit 115 c receives the release signal via the communication unit 113 and the server control unit 111, it stops the regulation signal output. As a result of it, because the output of the regulation signal is stopped, the server control unit 111 regards the incoming call notification signal from the telephone 140 a˜ 140 c as valid, and the incoming call regulation of the portable telephone 130 is canceled.

[0232] The following describes characteristic actions of the communication system 100 in this embodiment with reference to the FIG. 22.

[0233]FIG. 22 is a sequence diagram to show characteristic actions of the communication system 100 in a process an automobile in which the portable telephone 130 is brought goes through the area in the good and a bad communication statuses.

[0234] At first, when the automobile travels in the area in the good communication status, the portable telephone 130 sends an incoming call operation signal according to the user's operation to the server 110 via the base station 120, and requests it to connect to the telephone 140 a (Step S800).

[0235] The server 110 notifies that there is the incoming call from the portable telephone 130 to the telephone 140 a indicated in the incoming call operation signal (Step S802). As a result of it, the telephone 140 a rings an incoming call bell (Step S804). Then, when the user of the telephone 140 a who hears the incoming call bell takes the telephone 140 a off the hook to answer it, it makes it possible to communicate between the portable telephone 130 and the telephone 140 a, each of the users of the portable telephone 130 and the telephone 140 a start their communication (Step S806).

[0236] The portable telephone 130 always creates the latest prediction material data and sends it to the server 110. When the server 110 receives the prediction material data, it conducts prediction based on the prediction material data and updates prediction data 118 a based on its prediction result.

[0237] Next, when the automobile approaches the area in the bad communication such as a tunnel, the server 110 predicts the wireless communication will be disconnected after a specific time based on the prediction data 118 a (Step S812) and informs the time allowed for communication to the users of the portable telephone 130 and the telephone 140 a by sending announcement data to the portable telephone 130 and the telephone 140 a (Step S814). If the server 110 predicts the communication will become possible once again after the wireless communication is disconnected based on the prediction data 118 a (Step S816), it also sends the reconnection reporting data to the portable telephone 130 and the telephone 140 a and informs the time required for reconnection to the users of the portable telephone 130 and the telephone 140 a (Step S818).

[0238] Additionally, when the automobile approaches the area close to the tunnel, and the server 110 decides the time not allowed for communication due to the tunnel is less than the maximum holding time based on the prediction data 118 a (Step S820), it informs termination of the communication to the user of the portable telephone 130 as well as instructing the portable telephone 130 to automatically terminate the communication (Step S822). As a result of it, the portable telephone 130 terminates the communication without requiring any operations from the user (Step S824).

[0239] Then, when the automobile goes into the tunnel, the server 110 retains the connection with the telephone 140 a (Step S826), it puts the telephone 140 a on hold (Step S828).

[0240] Subsequently, when the automobile gets out from the tunnel and goes into the area in the good communication status, the server 110 connects the line once again with the portable telephone 130 (Step S830), and makes it possible to communicate between the portable telephone 130 and the telephone 140 a (Step S832).

[0241] Here, if the user of the portable telephone 130 puts the portable telephone 130 on the hook to terminate the communication, the communication between the portable telephone 130 and the telephone 140 a is manually terminated (Step S834).

[0242] Next, when the automobile goes into a tunnel once again, the wireless communication for the portable telephone 130 becomes impossible. Then, when the automobile approaches the end of this tunnel, the portable telephone predicts that the wireless communication will be possible soon based on the prediction data 118 a. Because there is another tunnel close by even if the automobile gets out from the current tunnel, the portable telephone 130 further predicts the time allowed for the wireless communication will be shorter than the minimum calling time (Step S836).

[0243] Then, when the automobile gets out from the tunnel and goes into the area in the good communication status right before the another aforementioned tunnel, the server 110 regulates incoming and outgoing calls of the portable telephone 130 (Step S838). In this way, the user does not have to make a call that may be suddenly disconnected so that it can avoid nuisances of the user.

[0244] Subsequently, when the automobile goes into the aforementioned another tunnel, the server 110 decides the automobile is in the area in the bad communication status once again, it cancels the regulation such as above to the portable telephone 130 (Step S840).

[0245] In this way, through the communication system 100 in this embodiment, even if the communication status is changed by moving, nuisances felt by the user of the portable telephone 130 and his calling party can be lightened.

[0246] Also, because the server 110 includes the map memory unit 116 and the communication status storage unit 117 in this embodiment, it makes it possible for the server 110 to collectively manage the map data 116 a and the communication status data 117 a. That is to say, if the map memory unit 116 and the communication status storage unit 117 are included in the portable telephone 130, the user of the portable telephone 130 is supposed to manage the map data 116 a and the communication status data 117 a and must make a change if there is a need to change these data. However, in this embodiment, because both data is managed under the server 110 as mentioned above, it is possible to eliminate an extra burden for the user of the portable telephone 130.

[0247] Furthermore, in this embodiment, the example is given on a bases that the portable telephone 130 is brought into the automobile and travels with the automobile; however, the same effects as above are provided even if the user carries the portable telephone 130 with him and travels with the portable telephone 130.

[0248] (Variation)

[0249] The following describes a variation example of the communication system in the above embodiment.

[0250] The communication system in this variation includes a plural number of portable telephones as a mobile communication device.

[0251]FIG. 23 is a system structure diagram to show the structure of the communication system in this variation.

[0252] As indicated in this FIG. 23, this communication system includes a portable telephone A130 a, a portable telephone B130 b, a server 160, base stations 120 and 121, the communication line network 150 and three telephones 140 a˜ 140 c.

[0253] The portable telephone A130 a and the portable telephone B130 b respectively contain the same functions and the same structure as the portable telephone 130 in the above embodiments. Although the server 160 has also the same structure as the server 110 in the above embodiment, actions taken by a prediction unit and a prediction processing unit in the server 160 are different from the actions taken by the prediction unit and the prediction processing unit in the server 110.

[0254] The prediction unit of the server 160 creates prediction data for the portable telephone A130 a and prediction data for the portable telephone B130 b based on each of prediction material data from the portable telephone A130 a and the portable telephone B130 b and stores these prediction data in the prediction data storage unit.

[0255] Then, a time informing unit, a connection unit and a call regulation unit in the prediction processing unit of the server 160 predict whether a communication line can be connected or not between the portable telephone A130 a and the portable telephone B130 b based on these prediction data That is to say, the time informing unit, the connection unit and the call regulation unit decide that the communication between the portable telephone A130 a and the portable telephone B130 b becomes possible only when a communication level is high and the wireless communication is predicted to be possible for both of the portable telephone A130 a and the portable telephone B130 b. Therefore, for example, when the wireless communication is predicted to be possible only for the portable telephone A130 a, and the wireless communication is predicted to be impossible for the portable telephone B130 b, the time informing unit, the connection unit and the call regulation unit respectively decide the communication between the portable telephone A130 a and the portable telephone B130 b is impossible.

[0256]FIG. 24 is an explanatory diagram to describe a method to predict time allowed for communication and time required for reconnection by the time informing unit of the server 160.

[0257] The time informing unit predicts, based on the prediction data, the wireless communication is impossible for the portable telephone A130 a for time between t3˜t4, whereas it is possible for time between t1˜t3 and time from t4. Additionally, the time informing unit predicts, based on the prediction data, the wireless communication is impossible for the portable telephone B130 b for time between t2˜t5, while it is possible for time between t1˜t2 and time from t5.

[0258] As a result of it, the time informing unit decides the communication between the portable telephone A130 a and the portable telephone B130 b is possible for the time between t1˜t2 and the time from t5, but it is impossible for the time between t2˜t5. Then, the time announcement predicts the time between t1˜t2 as the time allowed for communication and the time between t1˜t5 is the time required for reconnection.

[0259] In the way like this, this variation makes it possible to decide accurately whether communication is possible between portable telephones.

[0260] Although the communication device related to the present invention has been explained with reference to the embodiments and the variation, the present invention is not limited to them.

[0261] For example, though longitude and latitude are used to register position information to the communication status data 117 a in the embodiments, other description such as an address can be used to register it. Moreover, a communication level is registered with a 10 level grading method in the communication status data 117 a, but other description method such as a temporal average value of a radio wave density may be used in stead of the 10 level grading method.

[0262] In addition, the time reporting unit 115 a, the connection unit 115 b and the call regulation unit 115 c in the prediction processing unit 115 in the embodiment are respectively decide the line is disconnected when the communication status gets worse and the communication level becomes “1” and decide the line can be connected when the communication level becomes “2” or higher. However, a threshold value for such a communication level may be something other than “1”. Also, the above threshold value may be changed according to the user's operation of the operation unit 134 of the portable telephone 130. In this case, the portable telephone 130 sends standard information indicating a threshold value. When the prediction unit 115 of the server 110 obtains the standard information, it decides whether the line can be connected or not based on the threshold value indicated in the standard information. Furthermore, the maximum holding time or the minimum calling time may also be changed according to the user's operation of the operation unit 134 of the portable telephone 130. In this case, the portable telephone 130 sends a time setup signal indicating the maximum holding time or the minimum calling time in the same way as above. And when the connection unit 115 b and the call regulation unit 115 c of the prediction processing unit 115 of the server 110 respectively obtains the time setup signal, they use the maximum holding time or the minimum calling time indicated in the time setup signal.

[0263] Although the server 110, in the present embodiment includes the map memory unit 116, the navigation unit 119, the communication-status storage unit 117 and the road information obtaining unit 112, all or a part of these may be included in the portable telephone 130. In this case, the user of the portable telephone 130 can easily modify or update the map data 116 a of the map memory unit 116, the communication status data 117 a of the communication status storage unit 117, etc.

[0264] Or, the server 110 in the embodiment includes the navigation unit 119, the road information obtaining unit 112, the prediction 114, and the prediction processing unit 115, but these may be contained in the portable telephone 130. In this case, while the server 110 collectively manages the map data 116 a and the communication status data 117 a, it is possible to make the portable telephone 130 conduct navigation and prediction of the communication level. Also, it is possible for the portable telephone 130 to estimate its own position after a specific time, and for the server 110 to predict the communication level at the estimated position.

[0265] Additionally, the speed limit information is contained in the map data 116 a in the present embodiment, but average behavior information may also be included. This average behavior information indicates average speed of the portable telephone 130 and average direction that the portable telephone 130 travels on each road indicated on the map data 116 a. That is to say, when the prediction 114 estimates the position of the portable telephone 130 after a specific time, this average behavior information may be used. In this way, the prediction 114 can estimate the position of the portable telephone 130 more accurately.

[0266] Furthermore, it is possible to make the server control unit 111 automatically update this average behavior information. That is to say, the server control unit 111 calculates averages of the moving speed and the moving direction of the portable telephone 130 at a specific position by using the detected position information, the moving speed and the moving direction contained in the prediction material data sent from the portable telephone 130, and reflects its result on the average behavior information. In this way, the prediction 114 can estimate the position of the portable telephone 130 more accurately as well as omitting efforts to update the average speed information.

[0267] In addition, it is possible to make the server control unit 111 automatically update the communication status data 117 a. That is to say, because the server control unit 111 measures a radio wave density of the prediction material data send from the portable telephone 130 to the base station 120, the measurement result can be reflected on the communication level of the communication status data 117 a. In this way, the prediction 114 can predict the communication level of the portable telephone 130 more accurately as well as omitting tasks to update the communication status data 117 a.

[0268] Then, the present embodiment has the portable telephone 130 as a mobile communication device, but the portable telephone 130 may be structured as a hands-free device or an automobile telephone device. In this case, since the mobile communication device is carried on an automobile, it does not cause any problem even if the map memory unit 116, etc. are equipped with the mobile communication device as above and the device gets bigger. Also, if there is a terminal of a car navigation system within the automobile, functions of the car navigation may be used. In this case, the navigation unit 119, the map memory unit 116, etc. may be omitted from the server 110 so that the server 110 can be downsized. Moreover, if there is a device to obtain the road traffic information in the automobile, such a device may be used. In this case, the road information obtaining unit 112 may be omitted from the server 110 so that the server 110 can be made smaller.

[0269] The direction detecting unit 133 b in this embodiment detects a moving direction of the portable telephone 130 based on the detected position information, but it may be possible to make the direction detecting unit 133 b detect a direction of a global magnetic field (East-West-South-North), and detect a moving direction of the portable telephone 130 based on the detected result. Additionally, in the embodiment, though the speed detecting unit 133 c is made to detect the moving speed of the portable telephone 130 based on the detected position information, it is also possible to make the speed detecting unit 133 c detect the driving speed of the automobile and make this driving speed as a moving speed of the portable telephone 130 when portable telephone 130 is catered in the automobile.

[0270] Also, in the present embodiment, the connection unit 115 b of the prediction processing unit 115 automatically terminates the communication before the communication device 200 enters into an area in a bad communication status, but it is possible to have it terminated automatically after it enters into the area in the bad communication status. Furthermore, in the embodiment, the reconnection unit 115 b reconnects the server 110 with the portable telephone 130, it is possible to have the portable telephone 130 reconnect with the server 110.

[0271] Then, in the embodiment, one server 110 and one base station 120 are provided, but a plural number of them can be arranged. That is to say, a plural number of the base stations 120 can be located all over the nation, and the server 110 can be set for each base station 120. In this way, a load of work for the server 110 can be lightened. Additionally, the base station 120 may have the functions and structure of the server 110. 

What is claimed is:
 1. A communication device that is mobile and performs communication via a wireless communication medium comprising: a position detecting unit operable to detect own position; a communication status retaining unit operable to retain communication status data content indicating a wireless communication status at each position; a prediction unit operable to estimate a position of the communication device at the time when a specific time elapses according to the position detected by the position detecting unit, and predict the wireless communication status at the position with reference to the communication status data; and a processing unit operable to execute a handling process for disconnection of the communication due to deterioration of the wireless communication status based on a prediction result by the prediction unit.
 2. The communication device according to claim 1, wherein the prediction unit estimates a position of the communication device at the time when a specific time elapses based on the position detected by the position detecting unit, a moving direction of the communication device specified from a temporal transition of the position and a moving speed of the communication device specified from the temporal transition of the position.
 3. The communication device according to claim 1, wherein the communication device further includes a direction detecting unit that detects own moving direction and a speed detecting unit that detects own moving speed, and the prediction unit estimates a position of the communication device at the time when a specific time elapses based on the position detected by the position detecting unit, the moving direction detected by the direction detecting unit and the moving speed detected by the speed detecting unit.
 4. The communication device according to claim 1, wherein processing unit terminates the communication when the communication is predicted to be disconnected based on a prediction result by the prediction unit.
 5. The communication device according to claim 1, wherein processing unit specifies the wireless communication status at the position detected by the position detecting unit with reference to the communication status data, and executes a reconnection process when the disconnected communication is decided to be re-connectable based on the specified wireless communication status.
 6. The communication device according to claim 5, wherein the processing unit further reports, when predicting the communication is possible again based on the prediction result by the prediction unit after the communication is disconnected due to deterioration of the wireless communication status, a user and a user of other device as communication party on the time required to be re-connectable.
 7. The communication device according to claim 6, wherein the processing unit further decides, when predicting a state of the communication for the communication device is changed from incapable to capable based on the prediction result by the prediction unit, whether time allowed for the communication is shorter than a specific time or not, and regulates incoming and outgoing calls when deciding shorter.
 8. The communication device according to claim 7, wherein the prediction unit estimates, when obtaining route information indicating a route to a destination from a navigation unit that navigates the user to the destination, a position of the communication device at the time when a specific time elapses based on the position detected by the position detecting unit and the route indicated in the route information.
 9. The communication device according to claim 8, wherein the prediction unit further specifies, when obtaining traffic road information indicating a traffic condition on each road, a moving speed of the communication device according to the traffic road information content, and estimates a position of the communication device at the time when a specific time elapses.
 10. The communication device according to claim 1, wherein the processing unit reports, when predicting the line is disconnected based on the prediction result by the prediction unit, the user and a user of other device as a communication party that the communication is terminated.
 11. The communication device according to claim 10, wherein the processing unit makes the report to the user by presenting the report at least either in a character or with a graphic.
 12. The communication device according to claim 1, wherein the processing unit reports, when predicting the communication is disconnected at the time when a specific time elapses due to deterioration of the wireless communication status based on the prediction result by the prediction unit, the user and a user of other device as a communication party about the time allowed for the communication.
 13. The communication device according to claim 1, wherein the processing device reports, when predicting the communication becomes possible again after the communication is disconnected due to deterioration of the wireless communication status based on the prediction result by the prediction unit, a user and a user of other device as a communication party about the time required to be re-connectable.
 14. The communication device according to claim 1, wherein the processing unit decides, when predicting a state of the communication status for the communication device is changed from incapable to capable based on the prediction result by the prediction unit, whether time allowed for the communication is shorter than a specific time or not, and regulates incoming and outgoing calls when deciding be shorter.
 15. The communication device according to claim 1, wherein the prediction unit estimates, when obtaining the route information indicating a route to a destination from a navigation unit that navigates the user to the destination, a position of the communication device at the time when a specific time elapses based on the position detected by the position detecting unit and the route indicated in the route information.
 16. The communication device according to claim 15, wherein the prediction unit specifies, when obtaining the traffic route information content indicating a traffic condition on each road, a moving speed of the communication device according to the traffic road information and estimates a position of the communication device at the time when a specific time elapses.
 17. The communication device according to claim 15, wherein the prediction unit specifies, when obtaining speed limit information indicating a speed limit of each road, a moving speed of the communication device according to the speed limit information content, and estimates a position of the communication device at the time when a specific time elapses.
 18. The communication device according to claim 1, wherein the communication device is a portable telephone, a hands-free device, or an automobile telephone.
 19. A communication method used for a communication device that is mobile and performs communication via a wireless communication medium including: a position detecting step for detecting own position; a prediction step for estimating a position of the communication device at the time when a specific time elapses based on the position detected in the position detecting step, and predicting a wireless communication status at the position with reference to the communication status data content indicating the wireless communication status at each position; and a processing step for executing a handling process for disconnection of the communication due to deterioration of the wireless communication status based on the prediction result in the prediction step.
 20. The communication method according to claim 19, wherein at the processing step, the communication is terminated when the communication is predicted to be disconnected based on the prediction result in the prediction step.
 21. The communication method according to claim 20, wherein the processing step includes: a specifying sub-step for specifying the wireless communication status at the position detected in the position detecting step with reference to the communication status data; and a reconnecting sub-step for conducting a reconnection process when the disconnected communication is decided to be re-connectable based on the wireless communication status specified in the specifying sub-step.
 22. A program for a communication device that is mobile and performs communication via a wireless communication medium including: a position detecting step for detecting own position; a prediction step for estimating a position of the communication device at the time when a specific time elapses based on the position detected in the position detecting step and, predicting a wireless communication status at the position with reference to the communication status data content indicating the wireless communication status at each position; and a processing step for executing a handling process for disconnection of the communication due to deterioration of the wireless communication status based on a prediction result in the prediction step.
 23. A communication system where a mobile communication device communicates with other communication device via a wireless communication medium, comprising: a mobile communication device that performs wireless communication; a position detecting unit that detects a position of the mobile communication device; a communication status storage unit that retains communication status data content indicating a wireless communication status at each position; a prediction unit that estimates a position of the mobile communication device at the time when a specific time elapses based on the position detected by the position detecting unit, and predicts the wireless communication status at the position with reference to the communication status data; and a processing unit that executes a handling process for disconnection of the communication between the mobile communication device and other communication device due to deterioration of the communication status based on a prediction result by the prediction unit.
 24. The communication system according to claim 23, wherein the prediction unit estimates a position of the mobile communication device at the time when a specific time elapses based on the position detected by the position detecting device, a moving direction of the mobile communication device specified from a temporal transition of the position, and a moving speed of the mobile communication device specified from temporal transition of the position.
 25. The communication system according to claim 23, wherein the communication system further includes a direction detecting unit that detects a moving direction of the mobile communication device, and a speed detecting unit that detects a moving speed of the mobile communication device, and the prediction unit prediction unit estimates a position of the mobile communication device at the time when a specific time elapses based on the position detected by the position detecting unit and the moving direction detected by the direction detecting unit and the moving speed detected by the speed detecting unit.
 26. The communication system according to claim 23, wherein the processing unit has the mobile communication device terminate the communication when the communication between the mobile communication device and the communication device is predicted to be impossible based on the prediction result of the prediction unit.
 27. The communication system according to claim 23, wherein the communication system further includes a relaying unit that relays a signal exchanged between the mobile communication device and the communication device, and the processing unit specifies a wireless communication status at the position detected by the position detecting unit with reference to the communication status data, and maintains the communication between the relaying unit and the communication device and puts the communication device on hold when deciding the communication between the mobile communication device and the relaying unit becomes impossible based on the specified wireless communication status.
 28. The communication system according to claim 27, wherein the processing unit decides, when predicting the communication between the mobile communication device and the other communication device becomes impossible based on the prediction result by the prediction unit, the time not allowed for the communication is the same as or shorter than the maximum holding time, and puts the communication device on hold while the communication is not allowed when deciding the same as or shorter, and terminates the communication of the communication device when deciding longer.
 29. The communication system according to claim 28, wherein the mobile communication device sends a time setup signal indicating the maximum holding time, and the processing unit uses the maximum holding time indicated in the time setup signal sent from the mobile communication device.
 30. The communication system according to claim 28, wherein the processing unit further specifies a wireless communication status of the position detected by the position detecting unit with reference to the communication status data, and executes a reconnection process when the communication disconnected between the mobile communication device and other communication device is decided to be re-connectable based on the specified wireless communication status.
 31. The communication system according to claim 30, wherein the processing unit further sends, when predicting the communication between the mobile communication device and the communication device becomes capable again after being incapable based on the prediction result by the prediction unit, a reconnection time reporting signal reporting reconnection time required to be re-connectable, and the mobile communication device and the communication device report, when obtaining the reconnection time reporting signal, the reconnection time to each of the users.
 32. The communication system according to claim 31, wherein the prediction unit estimates, when obtaining route information indicating a route to a destination from a navigation unit that navigates the user of the mobile communication device to the destination, a position of the mobile communication device at the time when a specific time elapses based on the position detected by the position detecting unit and the route indicated in the route information.
 33. The communication system according to claim 32, wherein the prediction unit further specifies, when obtaining traffic road information indicating a traffic condition on each road, a moving speed of the mobile communication device according to the traffic road information and estimates a position of the mobile communication device at the time when a specific time elapses.
 34. The communication system according to claim 33, wherein the communication device is mobile and performs wireless communication, the prediction unit estimates each position of the mobile communication device and the communication device at the time when a specific time elapses and predicts a wireless communication status at each of the positions, the processing unit predicts the communication is possible between the mobile communication device and the communication device only when the wireless communication becomes simultaneously possible for both of the mobile communication device and the communication device based on the prediction result by the prediction unit.
 35. The communication system according to claim 23, wherein the processing unit specifies a wireless communication status of the position detected by the position detecting unit with reference to the communication status data, and executes a reconnection process when reconnection of the communication disconnected between the mobile communication device and other communication device is decided to be possible based on the specified wireless communication status.
 36. The communication system according to claim 23, wherein the processing unit sends, when predicting the communication taken place between the mobile communication device and the communication device becomes impossible based on the prediction result by the prediction unit, a termination reporting signal, which reports that the communication is terminated, to the mobile communication device and the communication device communicating with the mobile communication device, and the mobile communication device and the communication device reports each of users in advance that the communication is to be terminated when obtaining the termination reporting signal.
 37. The communication system according to claim 36, wherein the mobile communication device makes the report to the user by presenting the report at least either in a character or with a graphic.
 38. The communication system according to claim 36, wherein the mobile communication device and the communication device makes the report in advance through a voice.
 39. The communication system according to claim 23, wherein the processing unit sends, when predicting the communication taken place between the mobile communication device and the communication device becomes impossible at the time when a specific time elapses based on the prediction result by the prediction unit, a communication time reporting signal, which reports time allowed for the communication, to the mobile communication device and the communication device, and the mobile communication device and the communication device report the communication time to each of users when obtaining the communication time reporting signal.
 40. The communication system according to claim 23, wherein the processing unit sends, when predicting the communication taken place between the mobile communication device and the communication device becomes capable after being incapable based on the prediction result by the prediction unit, a reconnection time reporting signal, which reports on reconnection time required to be re-connectable, to the mobile communication device and communication device, the mobile communication device and the communication device report on the reconnection time to each of the users when obtaining the reconnection time reporting signal.
 41. The communication system according to claim 23, wherein the processing unit decides, when predicting the communication between the mobile communication device and the communication is changed from incapable to capable based on the prediction result by the prediction unit, whether the time allowed for the communication is shorter than minimum communication time or not, and regulates incoming and outgoing calls of the mobile communication device when deciding shorter.
 42. The communication system according to claim 41, wherein the mobile communication device sends a time setup signal indicating the minimum communication time, and the processing unit uses the minimum calling time indicated by the time setup signal sent from the mobile communication device.
 43. The communication system according to claim 23, wherein the prediction unit estimates, when obtaining the route information indicating a route to a destination from a navigation unit that navigates a user of the mobile communication device to the destination, a position of the mobile communication device at the time when a specific time elapses based on the position detected by the position detecting unit and the route indicated in the route information.
 44. The communication system according to claim 43, wherein the prediction unit specifies, when obtaining the traffic road information indicating a traffic condition on each road, a moving speed of the mobile communication device according to traffic road information, and estimates a position of the mobile communication device at the time when a specific time elapses.
 45. The communication system according to claim 43, wherein the prediction unit specifies, when a specific time elapses when obtaining the speed limit information indicating a speed limit of each road, a moving speed of the mobile communication device according to speed limit information and estimates a position of the mobile communication device at the time.
 46. The communication system according to claim 23, wherein the communication system further includes: a specifying unit operable to specify an average moving speed and an average moving direction of the mobile communication device at a specific position based on the position detected by the position detecting unit; and a retaining unit operable to retain a result specified by the specifying unit as average behavior information, and the prediction unit specifies the moving speed and moving direction of the mobile communication device according to the average behavior information and estimates a position of the mobile communication device at the time when a specific time elapses.
 47. The communication system according to claim 23, wherein the communication system further includes: a measurement unit operable to measure a signal intensity of a wireless signal sent from the mobile communication device; and an updating unit operable to update the communication status data based on a measurement result.
 48. The communication system according to claim 23, wherein the mobile communication device sends standard information indicating a standard to decide whether the communication between the mobile communication device and the communication device is possible or not from the wireless communication status predicted by the prediction unit, and the processing unit decides whether the communication is possible or not based on the standard indicated in the standard information when obtaining the standard information from the mobile communication device.
 49. The communication system according to claim 23, wherein the communication device is mobile and performs wireless communication, the prediction unit estimates each of positions of the mobile communication device and the communication device at the time when a specific time elapses and predicts a wireless communication status at each of the positions, the processing unit predicts the communication between the mobile communication device and the communication device is possible only when the wireless communication is simultaneously possible for both of the mobile communication device and the communication device based on the prediction result by the prediction unit.
 50. The communication system according to claim 23, wherein the mobile communication device is a portable telephone, a hands-free device or an automobile phone.
 51. A communication method for having a mobile communication device communicate with other communication device via a wireless communication medium including: a position detecting step for detecting a position of the mobile communication device that performs wireless communication; a prediction step for estimating a position of the mobile communication device at the time when a specific time elapses based on the position detected in the position detecting step, and for predicting a wireless communication status at the position with reference to the communication status data indicating the wireless communication status at each position; and a processing step for executing a handling process for disconnection of the communication between the mobile communication device and other communication device due to deterioration of the wireless communication status based on the prediction result in the prediction step.
 52. The communication method according to claim 51, wherein at the processing step, the mobile communication device terminates the communication when predicting the communication between the mobile communication device and the communication device becomes impossible based on the prediction result in the prediction step.
 53. The communication method according to claim 51, wherein the processing step includes: a specifying sub-step for specifying a wireless communication status at the position detected in the position detecting step with reference to the communication status data; a deciding sub-step for deciding whether the communication taken place between the mobile communication device and the communication device becomes impossible or not based on the wireless communication status specified in the specifying sub-step; and a holding sub-step for maintaining the communication between a relay unit and the communication device and putting the communication device on hold when the communication is decided to be impossible in the deciding sub-step.
 54. A program for a communication system where a mobile communication device communicates with other communication device via a wireless communication medium, including: a position detecting step for detecting a position of the mobile communication device that performs wireless communication; a prediction step for estimating a position of the mobile communication device at the time when a specific time elapses based on the position detected in the position detecting step and for predicting a wireless communication status at the position with reference to the communication status data indicating the wireless communication status at each position; and a processing step for executing a handling process for disconnection of the communication between the mobile communication device and other communication device due to deterioration of the wireless communication status based on a prediction result in the prediction step. 